I've found that "you're not stupid, you're just lazy" applies to most people who claim to be stupid.

Or....depressed for so long they started believe it. It's 4chan so if it's even real, that's way more likely

I mean it does make some things more difficult, but its more of a speed bump than a barrier. And a lot of the time decently attractive people will convince themselves they're ugly cause it helps justify their inaction.

To me it kinda sounds like covert narcissism "I'm so awful dumb pathetic and terrible I won't ever accomplish anything" and uses it as an excuse to be a lazy pos. A lot like boogie2988. Does it to drum up empathy, to enable his lazyness and uselessness.