That is because it is probably funnier TO women.
Take this list:
Top ten reasons for a guy to break up with a girl
1. Breasts aren't big enough
2. She won't give you a blow job
3. She will not listen to your well-crafted theory about why guys like you have a biological need to shag other women
4. She has a nagging Mum
5. She keeps wanting to talk after sex
6. She keeps wanting to talk when you want to watch the telly
7. She doesn't like the sports you do despite your best efforts to force her to watch the Superbowl
8. She moans when you don't believe her when she says she is fat
9. She expects you to remember every anniversary and birthday of her and all her friends
10. Breasts again
Now, that would be a list funnier to men than women, and some of them are very much reasons some men get aggravated with women, but it is not at all serious! And if a female member came along and said
"Those are shallow reasons to break up with a girl."
I would be like 'Huh? Well, DUHHH!"
This thread is just the same thing but with the sexes inverted