I don't think all political views are equivalent. Of course I'm supportive of opinions that I agree with, like you point out. Opinions I disagree with or espouse a world-view that is different than mine? Of course I'm fine with that. I read and own many authors I disagree with because I value the knowledge gained by reading them and understanding their words, even if I disagree.

Your example though? > Let’s say for advocating for arming every American or against gay marriage.

Arming them for what? To shoot gays? Yeah I would probably be pretty upset about that. Advocating ethnic cleansing? "Alternative facts" about vaccines?

If I were on Twitter or something I might tweet, or write a blog post about it trying to convince the publishers to change their mind or encouraging others to support different publishers. I don't think that makes me a book burner.

In reality though unless it was something truly vile or dangerous that crosses some sort of hard to define personal line I would probably not do anything at all... I'm not a despotic ruler who cannot abide the existence of mere words I disagree with...