Two major problems with present-day left-wing American politics:
1. The usual problems with leftism I've discussed before, but in particular the clamor among left-wingers - and the lefter the more bizarro and unhinged - for more government taxes, controls, etc.
2. The left's refusal to engage in a serious, responsible, accountable dialogue with the opposition (much less the strongest representatives among their opposition [e.g.]). (The irony of the left's defecating all over Habermas on this count is lost on them....) Today the leftist trend is ever more toward deplatforming, shaming, shunning, ignoring, strawmanning, contempt, hubris, flat-out dishonesty/evasion, ridicule, echo-chambering, mob intimidation, screaming and shouting, gaslighting, crying racism/sexism/transphobia/etc. on razor-thin pretexts, smearing . . . those are some big intellectual vices, and they explain a ton about the deplorable intellectual degeneration/atrophying/disease of the present-day left.
So, combine 1 with 2; what does that mean?
It means that the left seeks to impose their values and vision on the rest of America, through the ever-expanding power of the state -- but they don't want to engage in a good-faith conversation with those upon whom they seek to forcibly impose their values and vision.
This makes today's leftists something other than ordinary fellow citizens: it makes them domestic enemies.