Not every bully is a normie or chad/chadlite.
I had incel-tier dudes bullying me in the school days. Some do this to look "stronger" and to applease their normie peers. I can tell you this because I bullied other potential incels myself when I was *really* young, like when I was like 10yo (and I'm ashamed for it). But growing up I had a guy who bullied me, who was a manlet (actually shorter than I am) and low-T while that. One day I had enough of his shit and sent him flying through the corridor, and he never bullied me again. But of course, I could do jack shit against the taller, more physically imposing bullies.
But yeah, when it's a chad/high-T male doing it, your take might be correct. They have little competition (and naturally they don't see low tier men as competition lol), and they are often perfectionist faggots, so when they prey on the "weak" it's because they see them as undesirable in their perfect world and enjoys/feel better about themselves when they bully those kids.