I don't think it was a joke, but there are many gradations between "totally joking" and "actually serious." I think it's clear that most of them would not literally prefer their kids had cancer, but they are perfectly willing to vote that way in a meaningless poll to make a statement about how much they dislike feminism.
__________________
Iro's Top 100 Movies v3.0
I really just want you all angry and confused the whole time.