By elitist, I mean that old attitude (that still exists in many today) of "Only our style or lineage has the REAL stuff and everybody else is doing it wrong. (or can't do it at all)."
Or like "If someone uses an elbow (or a knee) in a fight, he/she is definitely MT, because only MT knows how to use elbows and knees."
Or "Since 98% of fights go to the ground, BJJ is the most effective martial art in the world." How they arrived at that percentage is TOTALLY unscientific, but was a '90s marketing campaign not based on reality. But it worked, because I've seen people still parroting that. BJJ is a brilliant method of floor fighting (I trained in it for awhile). It works extremely well, especially in one-on-one social (and some asocial) violence situations. But there are too many variables in asocial violence to say "the most effective" across the board.
Or, "TKD practitioners are the best kickers in he world."
Or "Bajiquan is the most high-level MA, and its fa-jing is the most powerful. We only train for One Strike Kill; Compared to us, Tanglangquan (Mantis) is fast but has no power or stability. And southern styles are lower-level and inferior to northern styles." Believe it or not, I encountered several practitioners in Taiwan from a certain well-known CMA institute who spouted this and believed it.
"Only Taiji/Xingyi/Bagua develop internal power, and are superior to 'external' styles."
"Wing Chun, with its economy of motion, is the most efficient, and only effective, kung fu system."
This also goes for attitudes among different lineages within the same general styles/systems.
I'm not picking on these particular systems; I'm only presenting a few examples of what I've either been told personally, or heard/read being given. Such people are what I call MA elitists. It comes from being ensconced in one's own little world, usually without much or any real-world experience around actual violence, and buying into the idea of style superiority.