Twitter is both. The records hop from 'left wing bias' to 'right wing bias' over and over. Plus, the internet skews left-progressive, which makes even centrist views seem right-conservative.

For every case of ACAB you can find a case of white hate or man hate with loads of retweets left alone or soft-endorsed, with the opposite being flagged for ToS violation. Both those statements are far more dominant among far-left.