All video is compressed, it's just a question of how much. That said, they released the video, someone linked it, it is remarkably clear, so I concede that he did have a knife. However, it doesn't look like he "charged at the cops" with it, rather he was running away, but didn't realize one of the cops had gotten on the other side of him. You can really see his oh shit moment when he realizes the person he's running toward is another cop, and he stops, but they're already shooting him (and each other, and several passengers) by then. What was the rush? The train wasn't going anywhere.
Ok, fair enough, he had a knife. I'll still criticize the cops for fucking shooting each other and bystanders over it as motherfucker tries to run away.
Would you pull it without being specifically asked to in a police encounter?
This basically amounts to "you should care about Haitians eating pets because you like animals", it overlooks that the veracity of the claim is not established...
Lock picking takes skill. I've defeated a deadbolt and doorknob with a cordless drill in ~15 seconds. And it's not even all that loud.