The only perspective that mattered on that foul is that the guy had the right to a place to land. When Giannis stepped under, it took that away, and that was the call. I can't call it a bad call. It's in the rules. I can say though that they allowed him to be mugged several times around the basket, and one of his travels was due to his being pushed so hard it forced him to take a step. But, that's all part of the game.