If you don't think 70% of the hashpower moving from bitcoin to an altcoin is a problem, I don't know what else to say.
Of course it is. And it's all part of the big block hijack plan.
It can't be stopped unless BCH becomes worthless to mine. We'll have to wait and see with that.
Miners are not our friends and they're not supposed to be, though it certainly has been taken a little further than I ever expected.