Something is very wrong with Twitter these days. I don't really understand algorithms particularly well but I'd assume the sheer amount of racism on Twitter is something to do with a change in algorithms. Racism on social media is far from a new thing - but what does seem to be relatively new is prominence and visibility of it.
For example, Stephen Lawrence is currently trending. You click on the trend and the top 4 posts are from racists throwing out examples of white people who have been killed by people of colour with "but what about THESE people" and taking issue with Stephen Lawrence being talked about. There are also a large number of tweets from people saying Stephen Lawrence was a drug dealer.
Again, these sort of comments aren't new - but to be the first ones you see when you click on a trending topic? Either we as a population are getting FAR more racist or someone, somehow, is intentionally boosting racist tweets and accounts. They're ranked higher up than the actual news reports on Stephen Lawrence themselves!