He's colorstruck. I make no judgement on his preference, but he's definitely showing you that with his comment.
Don't really want to bang on dude because to be real we all have something we "like"; his just carries a lot of historical self-hate baggage. Me? I'm drawn to short women 5'0 -- 5'3" or so. I don't know why and can't explain it at all, but I am. I'm 6'0" so it really isn't an issue and I date women of different heights, but if she looks like she could get a 10-day contract with the WNBA I might have to think on it a minute