Basically They Admitted that Sensei Seagal is the GOAT of all GOATs, his techniques are too lethal for mma, they know dis.
There's more to martial arts than just fighting.
What if you subscribe to the principal of nonviolence? How then can you defeat an opponent without hurting him?
Real life scenario: A mentally ill person is going psychotic. You need to subdue him but obviously no one wants to beat the shit out of a sick person just for being sick.
Well, muay thai is going to be pretty useless at that. BJJ is more useful -- but even an armbar or chokehold is a level too high because a psychotic person isn't going to "tap"; who's going to feel good about breaking a sick person's arm or choking them unconscious?
Maybe some drunk is bugging your girlfriend at a bar or trying to pick a fight with you -- but boxing him unconscious probably isn't good for your legal record, or getting into street fights isn't good for your white collar career..
So -- what do you use? Aikido.
These kinds of martial arts are terrible for fighting. But great for occupations like police officers, maybe psych ward personnel, etc.
The disrespect they get just because they're not useful for being locked in a cage with a half naked man is nonsense. They're actually more useful in real life occupations than just learning how to beat the shit out of someone.