Have we (as a society) become so PC we can't laugh at serious things?
Saying JimR's joke was about police brutality is like saying the joke about the chicken, the pig, the eggs & bacon breakfast and the difference between being involved and being committed (the chicken was involved, the pig was committed) is about why everybody should be vegetarian. It's not, the animals are used to illustrate, in a humorous way, the difference between two concepts. It's funny because you aren't the pig, family of the pig or friends with the pig because the pig is fictional. Even a hard-core vegan with a pot-bellied pig as a pet has got to chuckle a bit at the joke unless they have zero sense of humour.
Not joking (even obliquely) about police brutality, or any other problems in society, is not going to make them go away. You could even say the joke is against the brutality as clearly the unfortunate motorist is going to want the beating to stop, the beating is a bad thing to him same as the pig ending up as bacon is quite the commitment on its part.