I have the good fortune of having Facebook Friends who are more knowledgable and more experienced than me about activism and social change. The fact that we disagree about the means to achieve objectives that we have in common has challenged me to articulate an (unpopular?) point of view about anger as a force for social change.
Alex Himelfarb specifically, has written on his blog and on Facebook wall about anger as a motivating force for social change. As he points out, many people are disenfranchised, impoverished, dis-empowered and simply angry that their political systems and representatives have betrayed them. I too have felt betrayed – in particular by the Liberal party for reneging on its 2015 electoral promise to enact proportional representation. And I have felt angry about this betrayal as well as about the inaction by governments globally to deal with the climate crisis, not to mention the social inequalities among disenfranchised populations within countries and among countries.
So our reactions to ethical and social problems in society are not very different. We self identify as being in the “progressive camp”. Our differences are about “anger” as a motivation for changing things.
There is no doubt, that as a matter of sociological fact, Alex is correct in saying
Anger has in the past been an important force for building and expanding democracy, when those excluded from power and opportunity joined together in solidarity.
He also says:
Anger is always risky but can also be constructive, providing the impetus to overcome inertia and the inevitable resistance to transformative change.
In contrast, Alex says, there are ‘moderates’ who deny the existence of this anger and offer compromises. Think Joe Biden.
Alex cites recent psychological research on anger and political activism by Brett Ford at the University of Toronto showing that there is a correlation between anger and action for social change.
The conclusion of this research is that
…effective emotion regulation like reappraisal may be beneficial in the short-run by helping restore emotional well-being after upsetting political events but may also be costly in the long-run by reducing the potential for productive political action. 
The logical inference is that a social activist needs to harness anger (it motivates change) and couple it with “hope for a more just world in which people live in harmony with one another and nature” and “great things can happen” (from a Facebook post by Alex).
Again, Alex writes
it’s time to expand our perception of what’s possible, to stop denying or delegitimizing anger, but channeling the understandable anger in service of a national mission to tackle real challenges rather than invented ones and building a more just and sustainable future.
My perspective on Anger is that it is not a beneficial or trustworthy emotion. It is born of the pain and suffering we experience and see others experience but if it is the motivating force for action, the action will be imbued with the very energy it is trying to dispel.
However, anger should not be denied or repressed. It is a real human response – along with fear, indignation, anxiety, despair and a host of other emotions. These responses must be acknowledged and understood. From the point of view of an individual’s consciousness, we would say – these responses need to be held in awareness.
But the “legitimization” of anger might be another matter. If legitimization means that anger should be viewed as a beneficial force, I disagree.
Thich Nhat Hanh’s commentary on the first of the 5 Mindfulness Trainings – Reverence for Life makes this point:
We see the suffering caused by the destruction of life, and we undertake to cultivate compassion and use it as a source of energy for the protection of people, animals, plants, and minerals. The First Precept is a precept of compassion, karuna — the ability to remove suffering and transform it. When we see suffering, compassion is born in us.
The key in this passage is that understanding the suffering in ourselves and in others is the source of compassion and that compassionate action can relieve suffering. Compassion for suffering arises from being attuned and sensitive to our own suffering and the suffering of others, therefore it is necessary to remain in contact with it:
It is important for us to stay in touch with the suffering of the world. We need to nourish that awareness through many means — sounds, images, direct contact, visits, and so on — in order to keep compassion alive in us.
Nhat Hanh is inviting us not to avert our attention from suffering in the world – we have to face it, to see it, to recognize it. It takes courage because it is often hard to witness. Watching the suffering caused by climate change is hard enough. But there is also the ignorance and greed of people and corporations who regularly and consciously commit crimes of dis-information and cruelty that aggravate and perpetuate this suffering it is sometimes unbearable.
The Nhat Hanh continues:
… we must be careful not to take in too much. Any remedy must be taken in the proper dosage. We need to stay in touch with suffering only to the extent that we will not forget, so that compassion will flow within us and be a source of energy for our actions. If we use anger at injustice as the source for our energy, we may do something harmful, something that we will later regret. According to Buddhism, compassion is the only source of energy that is useful and safe. With compassion, your energy is born from insight; it is not blind energy.
Alex references the Marxist philosopher Gramsci who
warned that these in-between times were ripe for morbid symptoms, for monsters who use and amplify fear and anger.
Not only do demagogues and hate-mongers [Bannon / Lepen (father or daughter) et al.] stoke fear (e.g. of immigrants / refugees) and anger (e.g. against the establishment “swamp”) but they also rely on the self-righteous anger of the left (e.g. to start impeachment proceedings against the 45th president of the United States) to fuel the motivation of zealots on the right. It’s a never-ending cycle of polarization and extremism that triggers paranoia-fuelled violence (viz. the mass murder of Jews in a Pittsburg synagogue or of Muslims in a Quebec mosque).
Thich Nhat Hanh continues:
It never helps to draw a line and dismiss some people as enemies, even those who act violently. We have to approach them with love in our hearts and do our best to help them move in a direction of nonviolence. If we work for peace out of anger, we will never succeed. Peace is not an end. It can never come about through non-peaceful means.
To the political activist “Peace is not an end.” must sound like a mysterious Koan. What it means is – Peace can be the result [of an action], but only if that action is also the means by which it is performed. How something is done conditions both the results of that action and how people respond to it.
This view can easily be misconstrued as advocating a “wet-noodle” kind of attitude: “whatever shall be, shall be” or “don’t worry, be happy” or even “we need to just accept things as they are”. Not at all. The entire subject-matter of Buddhist practice – at the individual level but also at the social level – is to bring about the end of suffering by witnessing to it and bringing it to an end with love and understanding. It is an act of compassion to (fearlessly) stand up against racism and oppression to be a (peaceful) peace-activist (as Nhat Hanh himself has been all his adult life) and to bring about justice and equality.
In his statement of the 14 Mindfulness Trainings Nhat Hanh encourages his disciples to do their best “to speak out about situations of injustice, even when doing so may […] threaten our safety” and that “members of a spiritual community, we should […] take a clear stand against oppression and injustice” as well as to “strive to change the situation [of oppression and injustice], without taking sides in a conflict.”
By not taking sides, not holding to fixed views, not being oppositional (“them” and “us””), the Buddhist social activist can bring about freedom and equality, and peace and reconciliation by cultivating the conditions that are favourable for their manifestation.
From this perspective, non-violent resistance and activism is not only a question of restricting our actions to do no physical harm, it also has to do with cultivating compassionate intentions for those actions.
 Ford, B. Q., Feinberg, M., Lam, P., Mauss, I. B., & John, O. P. (2018). Using reappraisal to regulate negative emotion after the 2016 US Presidential election: Does emotion regulation trump political action?. Journal of personality and social psychology. https://psycnet.apa.org/record/2018-31269-001