Doesn't really matter since police officers are public officials. The bar for defaming a public official is actual malice, which is clearly not the case here. They need to prove that he deliberately said facts that he knew were false with the deliberate intention of harming them. It was also obviously a satirical song which further weakens the case. This is such a weak case it should have been thrown out before it ever reached trial.

Honestly, "actual malice" part probably the thing both parties here agree on existing. It's a series of diss tracks, they're inherently malicious.

You're just allowed to be maliciously right about things, if you like.