Indeed…
I think it’s fair to distinguish irrational insecurities from rational ones; wholly and entirely unrelated to someone’s over-reaction to them. If someone has a face full of acne scars, say, then feeling insecure about their looks is entirely rational, even though they might ‘overreact’. It’d be irrational though if someone had a single temporary spot... and thought their face looked like pizza because of it...
Or, in this scene, I’ve seen single fellas repeatedly, very pointedly, and very obviously excluded without warning from group play at a club. He’s in a tub, say; gets up for a smoke, or to go for a slash; returns and everyone in the hot tub is playing… if it happens several times, not unreasonable to get insecure about his presence there.