Is crossing your eyes rude?

Few days ago someone told me I shouldn't cross my eyes. I was wondering why because 1 she didn't give me an explanation for why and 2 no one ever told me not to.

That's not the problem though, the problem is I have a weakness in my eyes and sometimes I get severe headache because of my eyes, it's because my left eye is weaker and I'm wearing glasses (has been a while since I haven't and I know, it's bad)

I explain to her that I don't do it intentionally and it only happens out of my control, she told me because I look weird while doing that hahahaha 😅