I'm just against authoritarianism. If you support or worship tyrants past or present, then you're no friend of mine.
I don't think it is as black and white as you say though. In general I have faced more bigotry from modern conservatives than I have from leftists. At the same time though the unironic worship of the Soviet Union, or communist icons like Mao and Che leave a bad taste in my mouth. One killed millions of his own people and waged a cultural genocide against traditional Chinese culture and the elderly. Che on the other hand was a homophobic bigot who attempted to eliminate the queer people from Cuba. I understand criticizing Capitalism, and having faith in an economic system that has TBF never been implemented in the way Marx or Ingles would've wanted, but to worship the regimes that took the label and did horrible things in its name? I believe in learning from the past rather than trying to recreate it. If communists really want to succeed, they need to stop emulating a failed past, and push towards a new direction.