You have no proof of that.
That is simply your opinion backed up by not one single fact as presented by this article.
Maybe you would laugh at a person attacking you with a knife, but I wouldn’t, and neither would others, and neither did these police.
They were clearly within the law, and I don’t care if you refuse to understand that or not.
You can be sad that the girl died if you want. I can understand that reaction. I don’t personally have that reaction in this case, because she purposely made herself into a legitimate threat against the lives of others, and they dealt with her as such.
But I cannot sympathize with any attempt to hold these men criminally accountable for this action. They already have to deal with the fact that this girl forced them to kill her via her deadly actions.
I doubt they feel any worse than you do.