QI +1 on that.
=X= as it was pointed out, even if it's bed sheet golf just for fun, and no relationship plans involved, some of us just think that the chance a complete non-reader would be plainly too boring, that the risk isn't worth taking.
I'd personally even prefer a recognisable bookworm chick, let the look being secondary, over every majority labelled 'hottie' if I can see she's ignorant towards reading. Good sex is not a mindless activity. Somebody clearly unwilling to open her/himself for the mental depth only books can deliver is IMO most probably NOT being open minded enough to be an interesting! sexual partner.
I think that putting the OP in a nutshell would be:
"Assuming a high probability that a non-reader would be too boring to mean fun."
If that's the case I second it.
Just push ups with a boner ain't worth it.