What else would you call it? If someone calls a SWAT team to an address to scare someone, and the police enter and kill the person even if they are unarmed and innocent, what else it if not murder?
First, when one human kills another human, it's either a legally justified killing or murder. The majority of policy killings are justified and not murder. So that's "what else" anyone who understand the law and the English language would call it...unless you're just trying to stir things up with rhetoric. In that case you'd just use whatever word generates the most outrage ignoring the fact that you've used the word wrong.
As to your second question, I would call that murder. I would absolutely blame the person who called in the swatting, and depending on what happened I would blame the police.
Every police shooting has different circumstances. You can't lump them into one bucket and pass judgement.
There are very few instances of police murdering someone. I never claimed it doesn't happen, but "And since police murders in the US are so common" is just outright incorrect.