I'm from the UK. During a visit to Florida a few years ago, I witnessed a horrifying interaction between a white policeman and a black taxi driver (I was the passenger). That was the moment I realised why groups like Black Lives Matter exist. I'd say an anti-police message is an inevitable cultural result of institutionalised racism. Such literature shouldn't be suppressed but it should be instructive and highlight the need for reform, just as Charles Dickens highlighted the need for social reform in the UK in novels like Oliver Twist.