However I think the police have reason to be unhappy in this case. They risk their lives every day to deal with criminals, but now suddenly they are portrayed as the criminals. In every one of these instances they were dealing with people that already had criminal records (or were in the process of committing some crime), but now those same criminals are portrayed as the innocent victims.
They don't help themselves, in that case. Behaviour such as they've shown to De Blasio makes it sound like they're saying "we're above scrutiny, we're above accountability, our actions should not be questioned". By refusing to accept that there are questions over the way officers have handled recent high-profile incidents they're suggesting they either can't tell good policing from bad policing or just don't care. The (reported) response of many police officers to these cases seems to bely a basic ignorance of the concept of policing by consent; of the fact that they are policing for the people, not policing the people.
And to all the people that point out that Eric Garner was committing a crime: get a sense of proportion. An interaction with a police officer for sale of untaxed cigarettes should not result in the death of the alleged offender, unless the offender initiates some form of violence. The police should not have a license to get away with any kind of behaviour to someone who poses no public danger simply for refusal to cooperate (including resisting arrest). Now it's possible his death was a horrible coincidence that couldn't be foreseen, we'll have to hear from the pathologists on that one, but it's right that the incident is heavily scrutinised (including by journalists).