I realize that both men and women fib on those sites, but I can imagine how someone who's been forthright could be appalled at being quizzed about their weight. Plus, it's so subjective; what's overweight to one person may be "average" to another.
Obviously, if you find someone a total turn-off, don't go there. But if their face seems attractive or even neutral to you, you should give it a try. You may end up having so much fun you don't care so much about a little extra weight.
And keep in mind, Dan, you are not required to see them naked on the first date!