First, from Fox News:
Hours before an unhinged gunman shot and killed a New York City police officer sitting in her vehicle in the Bronx…www.foxnews.com
If this man was just released from inpatient psychiatric care a week prior, and his girlfriend called the police hours earlier with concerns about his behavior that night, I think saying he “just had legit hatred for police” is just ignoring facts to create a simple and convenient narrative. What he did was not a rational act in any way, so his mental health very much is central to the issue.
Second, to answer your question … if someone kills a police officer, do we blame the police or do we blame people who “incite violence”?
Okay, if someone literally tells someone else to go kill another person … yes, you can blame the person who instructed someone to kill someone else. If there is evidence you were instrumental in someone being killed, you can be held legally responsible, even if you did not pull the trigger yourself.
If that legal threshold is not met, I think you have to blame the person who actually killed someone.