The charges discussed in this article were obstruction charges brought against a minor that were administered during the course of an in-progress investigation. It's not quite the same as walking up to a cop on the street or in his car and hurling insults.
This article does a much better job that I could of detailing the nuances of 1st amendment jurisprudence. TLDR: It's a bad idea to go and hurl insults at a cop. The results of cases vary pretty wildly, but language has been narrowed to exclude insults directed towards and individual that are meant to illicit a violent response from a rational person from protected speech. When the accuser is a police officer, there does exist an expectation of heightened restraint on the officer's part over that of an ordinary citizen. Also in these cases the 'actions' (posturing, gesturing) are also taken into account to discover intent. Now, with this particular case, the actions and taunting were done towards an animal that is also police officer. It's a fascinating case really.