Wait, Choking Your Opponent With The Ropes Is Illegal Right?

So here’s an interesting video. These two fighters are going at it in a ring and at one point one of the fighters looked to lock in a triangle choke. Good for him right?

Well it would have been except for the fact that he was using the ring’s ropes to choke his opponent. So the referee did eventually stop them and put them back in the center of the ring, but it looks like it wasn’t because of the choking. The fighter who was getting choked tried to explain to the referee what was going on. The ref just put them back in the position, in the center of the ring, and let them continue.

What do you guys think, should the fighter have been DQ’ed?