The progressive left, which is most of its activist base is radicalised. Most of them are convinced they're living under 'fascism.'
This is the messaging constantly being pushed by Democrats and their media and even within lefty institutions in states all over the country.
It promotes violence as a response, especially within the mentally ill or the highly activist.
Politically I believe the big wigs of the Democratic party are happy with that situation as they have plausible deniability and can play word games about it.
To reaction to the Charlie Kirk assassination showed that while there are quality people on the left, as in all political spectrums (I know lefties I like)....there's a huge amount who are tribal to the point of celebrating that murder and at best not caring that it happened.