It's a shitty rule, and while I don't want to absolve Yan it could have been avoided if they got rid of the "hands on the ground mean you're grounded" which has always been dumb. Yan said he was focused on making sure his hands weren't on the ground which is a dumb answer but it's also dumb that he even has to think that.
The reason I've tried to side with Yan here a bit is that while it was an illegal strike, you're still allowed to do that strike most of the time. That's why I personally consider it "unintentional" as opposed to if he had stomped on his head, punched a ref, or did something that is obviously illegal.
As for the ref talking about a DQ with Sterling there, agreed he shouldn't have. But I also doubt that made a difference as I would be surprised if Sterling in that situation could piece together that DQ=belt as it's a rare situation even when your brain is at full capacity which his certainly wasn't.