They do both. They're essentially the only (good) ASIC manufacturer for Bitcoin at the moment, and they also run mining farms and are involved with mining pools. A good chunk of their business revolve around Bitcoin, so there's no way they're going to harm Bitcoin by going for 51% of the hashrate. It has to be noted that 51% only makes attacks possible, not necessarily probable.

Either way, I'd say that throttling their hashrate output would still be a better business move than scaring away Bitcoin users. They probably deserve the negative image that most in the crypto world has of them, but they're still a business that aims to profit at the end of the day.