If you march around synagogues with torches chanting "the jews will not replace us" while giving the roman salute, there is no bellyaching when people associate you with nazis. https://www.washingtonpost.com/news/acts-of-faith/wp/2017/08...
If you’re allowed to coalesce the right into their extremists, the same should hold true for the left. At least in a society based on liberalism.
I’m of the belief that fewer black folks being shot by police is a noble cause, so I feel positive about BLM. I also feel positive about some of the constitutional and militia groups because IMO the scale and corruption of the US government ALSO requires attention.
I don’t like racial bigotry or communism so I will vehemently denounce such groups.
Where? I've seen the right wing extreme fringe existing in real life. Never seen what you just described. If it actually exists, it's hidden well enough to not bother me.