The problem is that there is a ton of the converse: treating a political opinion like it's bigotry. Complete with altered definitions of words so you can use the big guns like "racism" on actions like voting for a candidate who supports fiscal responsibility when you think that's the best way to deliver a good life to everyone.

And then, with rhetorical weapons heavily dulled from overuse, the actual bigots come out and say that they just have a political opinion. What are you going to say to them? Racist? Bigot? And that's supposed to hurt?

I think you mostly have cause and effect upside-down here: to gain political advantage, political differences were treated as bigotry. This released some of the pressure on actual bigotry.

To reverse this, rather than saying stuff like, "I will never agree to debate whether someone has a right to exist," you should explore the issues that you would debate, which by this standard is pretty much everyone because nobody--very very very very close to actually nobody--argues that anyone doesn't have a right to exist save, sometimes, for people who have committed sufficiently heinous crimes.

If what you actually mean is, "I reserve the right to declare that you think someone shouldn't exist, over your objections, and then not talk to you," that's not such a noble-sounding statement. Neither is, "I will never agree to debate whether someone has a right to do whatever they want regardless of how society is structured and have other people respect their actions." (As you correctly point out, some things are really not worthy of respect.)

You make a lot of reasonable-enough points about opposing really horrible attitudes and behavior. But people are almost entirely on that page already. To the extent that they're leaving it, they're leaving it because we're not making adequate distinctions between being on that page and being off it.

There's a lot of room between "mint chocolate chip is better than Cherry Garcia" and "we should never rest until every Zoroastrian is dead". All the interesting action happens in between those extremes, but you don't give any guidance in what to do in anything but black and white cases.