I think it's a consequence of poor representation by many actual tankies, multiplied by a concentrated effort to silence any critique of Biden to boost his ratings as someone just a bit less evil than Trump.
This is a big clusterfuck, and I hope to have a better dialogue between authoritarian socialists, liberal socialists and people who consider themselves "left" because they vote Democrat (Murica did a great job at straying people away from actual socialism).
Hostility won't help either side, but tankies are stubborn and Biden-prophets are relentless, dividing the community of people who all want a more equal and happy world.