Cops are discouraged from having opinions anymore, basically. You disagree with what he's saying therefore, he's wrong for saying it.
FTR, it was a misstep in judgement to call out media members and anyone "spreading the rhetoric that cops are the enemy" on the record and on a national platform like that. And given the fact that the shooting resulted from fabricated evidence, it makes him, and everyone in law enforcement, look dirty.
I disagree that stating "People think that cops need to be reformed. They need to be killed..." is simply referring to "people" and not specifically LEO's. It's on his Twitter account and plain as day.