In the Dorismond case (and maybe the other one, too), there were conflicting accounts over whether the undercover cops had actually identified themselves as such.
The cops definitely identified themselves in the Baez case. They had already arrested his brother. We could spend the rest of the day going over NY history. The original poster's point was that the idea that Giuliani wasn't well liked is a media revision. The people who didn't like him because trumped up charges of him condoning police brutality didn't vote for him in the first place. And the media played to that by manipulating the stories to make Giuliani seem worse. Anthony Baez was twice the size of the officer who choked him to death.