It's ridiculous because of course it's entirely socially conditioned and often rooted in racism, sexist double standards etc.
For example, black women and Asian men have a far lower rate of swipes (or whatever it is) on Tinder (never used it so excuse my lack of terminology). I know soooooo many people who ask me stupid questions about my Asian husband (and yes, 90% of them are about his penis size and those people are all twats) and how I can POSSIBLY be attracted to him.
To act like it's all primal/physical is really silly. It's conditioned. As convecticle said, so much of it is based on 'I'm a ickle tiny girly and I need big stwong man to take care of me." How many women say 'I only like short, chubby, balding guys with extremely weak arms'? How many men say 'I only like fat, frizzy-haired women with hairy legs and massive biceps?' If it was truly a personal preference, you'd get a lot more people saying those kinds of things.
As an example, here in Asia, a small head is considered attractive. We wouldn't even think of it in the west, but that's what they look at. I have seen women who I think of as stunning who my husband thinks look plain weird/ugly. (An example is Salma Hayek - she's considered beautiful in the west, but extremely ugly in Asia because she has what they consider to be a big head. My husband literally thought her being portrayed as sexy in one movie we saw was a joke and that the movie was a comedy based on her being ugly.)
It just seems a facile thing to even talk about. Nothing wrong with having an ideal type but people who come out with shit like 'I don't date short/black/Asian/chubby/whatever' men/women just come across as pretty shallow.