You likely hold many such superficial judgements, we all do about something or other. I don't think I would frame it as "mental illness" without expecting a lot of pushback from such an inflammatory statement. Normal, healthy people make judgements all day long based on the most superficial of ideas and perceptions, the question is how much you personally care.

If it's strangers on the internet you're just bullshitting with, I can't imagine caring about how some stranger perceives you. But these things can become self-harmful if you're genuinely trying to be heard and understood about something that's important to you. If you've spent any amount of time on social media (including forums like this) I'm sure you've seen this play out over and over, where people end up deeply stressed because they're talking past each other and dismissing each other's actual feelings about things that are important to each other.

This is what I decry, the lack of effort to be heard about important ideas, even if subjectively important, we're all collectively really neglecting effort and embracing anti-intellectual catchphrases (just put the X in the bag, the curtains were just blue, I ain't readin all that, etc.) and making our lack of effort to communicate other people's problem when it goes wrong.

If you think none of this matters, end up in a role of responsibility and have to spend a month interviewing people for a role of great responsibility and sifting through the masses of young people who make zero effort and feel entitled to rewards for it.