Lots of people say that you shouldn't release a hold when someone taps, but instead wait for the referee to stop it. I understand that is probably what they are told and is to be on the safe side. This is also mostly harmless when it comes to chokes.
HOWEVER, there are infinite examples of fighters who feel or hear a tap and instantly release the hold without the referee ever even knowing what happened. There are infinitesimal situations where a fighter taps and the hold is released before the ref sees it, and the fighter denies tapping. It has happened, but it is so rare, and the fighter who does this on a nationally broadcast fight is going to get a ton of grief for it. It is also very likely that Dana would overrule the result of the fight if it happened to make a difference in a match.
My point is...fighters can release when guys tap. They don't need to wait for the ref. The fighters that tap almost always have the respect to not claim they didn't. When that does happen, replays are going to catch it and that fighter is going to get ostracized, and likely have Dana make the result right regardless of what happens after that. Finally, and most importantly, it keeps the fighters safe. Most fighters recognize that if they are being submitted, they'd prefer their opponent release when they tap and will show the same respect.
Given all of this, Rousimar holding and further twisting despite somewhere in the neighborhood of 10 taps and screaming from his opponent is particularly disturbing. If it was an isolated incident, I'd give the fighter the benefit of the doubt. This guy has done it multiple times in the UFC, multiple times in MMA fights outside of the UFC, and multiple times in bjj competitions. He is dangerous, beyond the scope of the sporting activity that the competitors agree to participate in.
I love this sport, and I love submissions. I don't want to see people get seriously hurt and definitely not maimed while fighting. When they are too tough for their own good, it is going to happen. When they submit, agreeing they have been bested, it should never happen.