The disruptive students I'm thinking of were basically juvenile delinquents, not future math PhDs who trolled on homework sometimes. The girl who dropped acid in economics class, the girl who peed on the floor in math class, the guy who beat the shit out of another guy in the cafeteria, the two girls who were literally ripping each other's hair out in the hallway until my history teacher pulled them off of each other. There weren't that many of them, but in a class of 30 students a single one of them (just 3%) can guarantee no one learns anything.
Don't take this hindsight for granted. Nobody would have said I was a future math PhD, and several of my teachers were quite convinced that I'd never amount to shit. I was a bad student, and got in trouble for all sorts of shit. Numerous teachers gave up on me very early in my education: my third grade teacher moved my desk to face the corner as a "permanent" punishment because I was disruptive. It was a collaborative effort between my parents and a few good teachers to even get me through high school, and I had no interest in higher education. It was only after a few years bored as fuck in web development that I started to wonder if I could make something more of myself, that I went back to school.
