TBH, no rules expert, but I don’t think it from a late out of bounds hit, but you can’t really ever get away with going head-to-head on a QB. No low tackles, stay away from their head, don’t take more than 2 steps, don’t body them to the ground, etc. I think that’s why it was Unsportsmanlike, but I could be wrong.
You ain’t wrong, though, refs wanted their 15 minutes of fame.