Problem is, it's always been taboo in conservative circles as well. That is the great problem of our day. All these political ideologues espouse beliefs contrary to the good of large numbers of people in our society. They give speeches about how it's not "us" but the other side who are the bad guys, but then they all send their pet terrorists out to riot, loot, and in the case of the capitol attackers gather intel to hand over to our nation's adversaries.
These political extremists are simply bad people all the way around. No matter what way you look at it.
It's long been my opinion however, that they need to be dealt with. Just as the pet terrorists they control need to be dealt with. I have zero respect for them, and look forward to seeing a lot of these ideological extremist organizations dismantled over the next decade.
It's time to turn up the heat on these people so high that they won't know who to trust.
Unfortunately, I don't think we're going to get dismantling of extremists. Rather, I see the opposite, further partisanship where one's extremists are ignored and only the enemy should be criticised. The rapid crystallization of the Pro censorship movement on traditionally free speech supporting circles for their political opponents seems to support this.
All political violence should be treated equally.
I also think that all races/genders/etc should be treated equally but even that has become taboo in progressive circles. Which is probably using the same sort of mental gymnastics that justifies some violence but not vilifies others.