The ones doing this are displaying a level of stupidity (IMHO) that has not been displayed by the shooter(s) to date. Doesn't add up to me.
But it's just my onw specualtion and opinion and I clearly don't have access to all the information that LE has. And that's all it is, noting more, nothing less.
I hope I am wrong.
As an extortion attempt, there are a lot easier targets to extort than the government.
My best guess, and it's no better than anyone else's, is that the sniper is having fun with the police. He's screwing with all of us.