Hong Kong has been a mess nearly all game.
There are a bunch of small airlines flying out there, doing about the same thing all over the place.
I've even seen DC-9-30's, flying out of Hong Kong, doing that to cities with less than 25k pax too.
How they're making money - or even how they are even able to get DC-9's in the first place is beyond me. I suspect they are either being fed from a larger alliance member airline, or they're leasing them.
I don't know. Now its getting crowded with all the alliance cronies too.
You just have to live with it, I've been doing so all game.