Mr. Shum is just a troll. He has NO love for fish, he has a love for pissing off animal lovers and starting controversies. I imagine he likes Bettas, but he does not care for them... And just wanted as many in as small a space as possible, for the joy of having fish. He obviously does not care for their well-being.
I'd also imagine Mr. Shum here is not very old. I picture a teenage boy who found a big ol' tank in his garage, wanted something to stick in it, and knew that the bettas were very pretty fish, and they were CHEAP and EASY to find. So, he bought a bunch of them and shoved them in the tank, with no consideration or research. I'm 95% posotive he knows his fish are in hell, and that he is just getting joy from pissing everyone off. If I were you, I'd realize his ways are not going to change, unless you offer him money. Offer to guy the bettas for 10 bucks a peice, I'm sure he'll move them out of that tank.
Katy