Not to belittle, but to explore. In the example the author gives the situation seems pretty cut and dry. It's an understandable and necessary self protective position to take. However, she then goes on to say that anyone who is racist, sexist, homophobic, anti-semitic etc or who keeps friends that are such cannot be in her life.

Who gets to define what counts as racism? What happens when two BIPOC disagree on something? What happens when BLM proponents make antisemitic statements? As documented here: https://www.glamourmagazine.co.uk/article/black-lives-matter-antisemitic-tweet

In a pluralistic society, the existence of one group often acts counter to another - and this is complicated. As exemplified by the split in feminism around trans-people in female safe spaces. The idea of having a simplistic 'I'm the good guy' narrative doesn't work in a complicated world - it's just a popular form of virtue signalling. It's something that a lot of writers on this platform do, and make lots of money from doing so - but all it really does is further inflame racial tensions. In short, this sort of anti-racism only makes racism more prevalent.

I read an excellent and nuanced article about disengagement from this process yesterday - which I highly recommend https://medium.com/love-everyone/i-watched-a-chat-between-two-ex-black-lives-matter-fans-25b34aaafd6e