I do feel that some parts of female society treat childless people as second class citizens. Sometimes I feel this pity vibe coming from people who have families, some have even pestered me rudely asking when I'm going to get on with ttc!! It seems strange that while my partner and I are holding off from starting a family until we are financially stable, there are plenty of mums that just get on with it and live off benefits. And I am the one to be pitied?? Shouldn't I be patted on the back for being sensible? I just know that if I am lucky enough to have kids, several of my friends/family members will suddenly start speaking to me more often... 
On the other hand being childless does have its advantages. Yeah you wouldn't get as much benefits if you went begging for money from the state. But you have got so much more freedom than someone with kids. You can save up for holidays and shopping and hobbies! You don't have to worry about childminders, organising things for all the family to do, budgeting to allow for school uniforms and a huge groceries bill! You can just swan off on a day out, at the drop of a hat. And if you're single too you don't even have to tell anyone where you're going!
DP and I don't have a lot of money to play with but we do have some hobbies that we spend a lot of time on and although we are looking forward to the future, we are also making the most of the pre-kids lifestyle by doing a lot of laid-back chilling! 
I think this woman is obviously bitter about more than just the way she is treated, she doesn't state clearly whether she is ok with being single and childless or not ok with it. I would guess the latter. She has picked on MN as an example of typical mum-centric discussions, but actually I have been welcomed here and as a non-maternal type I am not actually a rarity here.