For what my opinion is worth, in the far past when such opinions were first formed, I read what I now assume was shyness and awkwardness as aloof disinterest in pretty much all of humankind and/or a general preference for computers, books and other activities involving aloneness.

Unfortunately, I've absolutely no advice as to how you might remedy that. I've also never seen you flirt, so can't say whether it's had the adverse affect or not. (Or have I seen you flirt and just completely failed to pick up that that's what you were doing?)