Women on PoF are garbage. That's your first problem. They're living in a fantasyworld.
What you need to realize is, the dating field is full of losers. Hence, why they're single, and dating around. Contrary to their delusional claims - they can't not find the right man - a lot of them aren't the right women (they only think they are, and feel entitled to someone who is - as they ***** about everything... They're really just conceited and full of themselves).
The truth is, most quality people are taken already. They get nabbed up quick. So, you're left with a lot of garbage. Players, *****es, retards, skanks, bad girls, etc. This is why being a bad boy can be so effective - because they attract a lot of garbage, and there's plenty to go 'round. It's their whole lifestyle - to bang trashy single women. Most single women are trashy, so there you go.
These girls typically jump from guy to guy, play games, attention *****, use people, act like *****es, are stuck up and snobby, and all these things - and that's why they're always single. Of course, that wont stop them from *****ing and complaining, playing the victim, claiming nice people finish last, blaming others for everything, calling everyone *******s, and so forth. Delusion and denial is common among failures - as is finger-pointing.
It's no different than a loser who has no friends due to being unlikeable (different from shy; just a worthless person). They're going to blame everyone else, but there's clearly a reason for this. You'll find a lot of these single women don't have many close friends, either - because no one can stand them. Their personalities and attitudes suck. Only if they're hot do they get a lot of attention from guys, and have "lots of guy friends" (who only want to have sex with them, since they can't stand them, either).
This is just something you have to deal with. But, you can better your odds if you choose the right women. Someone with all these issues and ****ty personalities is going to be single and friendless for a reason. Hence, going on PoF in the first place. You might as well go look for women in the ghetto, or the bar, or in the dumpster. You're gonna find the same types there. It's where they flock to. They'll be *****ing and whining about not being able to find a good man, too - as they're sucking off random guys for crack and vodka. "Where are all the nice guys? Why can't I find a good man?" -- says the loser.
So yeah, the dating field is ****. That's just reality. Gotta weed through a lot of trash; don't sympathize with, or give your heart to anybody. No expectations is an absolute must. Always pay attention, believe nothing, trust no one, weed through the BS, and make sure they're decent people. If you don't do that, and keep attracting losers - that's your fault for sticking through their bull****. Much like the girl who complains about an ******* - you're doing the same thing. "Why is this girl such an *******?" - as you keep pining after her, and potentially obsessing over it. Likely for the same reasons: desperation, denial, unhappiness, wanting a trophy girl, etc.
A good rule of thumb is to never obsess over losers - because its just the way they are. Who cares what they do? They can eat ****. Associate with quality, decent people, and you won't have to worry about it. They're not worth worrying about, anyway. Just say to yourself (or them), "yeah, I see why no one likes you / them".
Typically, if someone is obsessing over and *****ing about losers - its because they're associating with them. Or trying to attract them. Or whatever. Knock it off. Who cares if they're "hot"? A loser is still a loser.
Edit: Also, be honest with yourself... Do you like losers? Some people do. They like to ***** and complain about all the things they do, and have issues of their own. Self-reflection is a must whenever there's a repeated negative pattern. Who are YOU chasing after, associating with, etc, and why? Some people like to be miserable, and keep feeding their hate so they can be. It's a crazy world.