Well said! I'm sorry you had to endure that. I think that situation has happened to more of us than we even realize-- not all plagiarists get caught. It's kind of a scary thought.
Here in Houston there is a down-the-middle divide on the Whole YouTube Thing-- several companies have their own YouTube channels where they post full-length works; several others are vehemently against it; some don't even release performance footage to their dancers for fear their works will end up on YT and later be plagiarized by lazy choreographers (such as the one you encountered). It's a gamble anytime you post your original work on the internet.