This is one that I deal with all the time with the extreme right, the extreme left, the extreme LGBTQ..., the extreme vegans etc.
You have to negotiate!
No, we don't. Some starting positions are so ridiculous that they leave no room for negotiation. No one is owed a negotiation. Sometimes the answer is, "No."
EDIT: A couple of pedantic extremist apologists and a small brigade of their friends tried to shout and insult me down. They failed. They weren't interested in a conversation, just silencing someone whose message they didn't like. Do you know how I know this? Not a single one of them asked me to explain myself. Not a single one asked me why am extremist is an extremist.
All extremists have a pathological belief that they are somehow superior and that that superiority justified their anti-social behavior. So neo-Nazi extremists have a pathological belief that they are racially superior and that that superiority justifies harassing, intimidating, and threatening people they believe are racially inferior to leave. Vegan extremist believe that they are morally superior and that that moral superiority justifies their harassing, intimidating, and bullying restaurateurs butchers, grocers, farmers, and their customers to change their diets to comply with the extremists beliefs.
So, the (pedantic) details may be different but the underlying pathology is the same.
An extremist is an extremist. They're all pathological assholes with grandiose delusions.