[necovek]

A person who is like that is rarely called a "lovely person": how does that lovely interaction look like when you point such an egregious flaw out to them?

And tbh, this has nothing to do with being self-taught: by the time I enrolled in CS program, I was arguably self-taught and could spot issues like this myself. But I pride myself in learning from my mistakes and learning fast.

So it's more likely a character thing: if you are willing to admit when you are wrong, you'll learn much faster!