It's tough. I'd encourage you to take a step back and reflect on arguments used from many positions. Currently a lot of discourse is breaking down and polarization increasing because of a lack of reflection and understanding one's own biases and the arguments one's making and where they're coming from. No one has a monopoly on bad faith (unless you're considering humanity as a whole). I've found Jonathan Haidt's The Righteous Mind[0] to be really insightful and useful in this regard, particularly if one has a goal of effecting meaningful change.

[0]: https://en.wikipedia.org/wiki/The_Righteous_Mind

Edit: Re-reading this, it's coming off harsher than intended. I likely need to eat something. Apologies.

I'm not saying anyone has a monopoly on bad faith. Your rebuke isn't overly harsh. If your criticisms were more pointed I may have a more directed response... but I'm not sure exactly what you have in mind when you say "discourse is breaking down", etc.

(EDIT: I'm perfectly aware I'm generalizing and speaking of stereotypes when I say "average alt-right person", but Sartre wasn't exactly describing separate individuals either...)

Are those generalizations useful and constructive, particularly in this case? I'd argue strongly no. In fact, I'd argue they're actively counter-productive. One of the self-described reasons for the feeling of alienation that many have expressed is exactly this type of generalization. If you have a goal of working against, this, it seems that you're actually reinforcing it when you do so.

I think if those generalizations let us draw a useful parallel to a historical example, we can note the similarities (and differences) and apply lessons learned from that era to our own.

(Not that Sartre included a chapter called "How to Have Avoided The Whole Affair" in his book...)