It's very much a metaphorical comment for her; normal men, according to her worldview, obviously check out womans titties every chance they get. She's being incredibly rude and arrogant. "If he's not checking me out, he very obviously has serious mental health problems, or is just straight up not human." The arrogant half is the expectation that even if a normal man had the capability to ignore some other woman's titties, no normal man would ever be able to ignore hers.
She would likely consider gay men to be an aberration too.
Telling someone they're an alien for not being interested in you is very definitely rude. Sure, you put effort into your appearance, you have pride in your looks. There's nothing wrong with that. It's when you take that rejection out on someone else that it becomes a problem. Here, it's a mild issue, almost certainly intended to be a fourth wall wink at the readers more than anything else, but at the end of the day, she called clark an alien because he turned her advances down.
Using words like "Abnormal", "Weird", or "An Aberration" don't really have the same connotations as "From another planet." It's not a negative thing. More often I've seen it used in a positive way, like when someone does something good that most people wouldn't.
To be for frank Clarks mannerisms are stronger, and she should’ve been more forward in the sense of asking him out. Rather than trying to pin him into a corner to pick on him. If he had played along towards her desires ahead could easily played various other cards.