Or because a lot of the midwest is hella racist, but either way. You don't really have to show me the screenshots, I grew up here. I've also played and watched hockey under at least 4-6 different rule books.
The video slow mo you showed makes it look less bad. Minus his rap sheet (in general, not just with the blues) it probably gets way less of a look. I think the problem is whether or not he was trying to run him, which he probably wasn't to be honest, he's the kind of player that doesn't have the presence of mind about endangering other players in the moment. He's reckless at worst and undisciplined at best. Once you have that rep in a league it's kinda hard not to get piled on especially if a goalie is on the ice. Even if it's not your fault. We have a saying in this house "Wilson to the box!" whenever a whistle blows in a caps game... you get the point.
No excuse for the fans by any means whatsoever, no matter how much I hate dangerous / reckless hockey players, racism is obviously inexcusable.