Watching the slo mo of the replay, there is an argument that the referee should have not allowed the goal because of a dangerous play. Not saying I would have but stranger things have happened. The rule that I found:
Scissors or bicycle kicks are permitted in the game unless an opponent is within playing distance and the kickers foot is, in the opinion of the Referee, dangerously high so as to endanger the opponent. If no one is within playing distance, there can be no offense.
I wondered about this too.
ML/NJ
The opposing defender didn’t raise too much of a stink (and they usually will for even the most innocuous instances of this), so maybe they weren’t as close as the TV angle suggested.