I realize that you are feeling angry at your ex girlfriend and are venting, so even though I am female, I won't take your insults about "all females" personally. But I did want to say that your description of us all as being selfish and playing games is sorely incorrect. Just because one girl hurt you, you can't discredit all of womankind.
I have had men treat me the exact same way that you have described here. I was cheated on by an ex I was with for 8 years and I had treated him very well. I am not exaggerating here. He even told me I treated him better than anyone ever had and that he didn't deserve me. My latest ex pushed and pushed for a long distance relationship with me (though I was skeptical at first) only to have him dump me out of nowhere after a year together (and a very wonderful vacation) for a girl closer to him blaming "the distance". He and I got along famously for the majority of the time and only argued maybe two or three times over very minor things during the year we were together. The point is I am female and treated both of them well. I wasn't clingy. I was faithful. We had fun together. Chemistry. Intimacy. I loved them both and tried to make it work as best as I could. I had the best of intentions with both of them.
That out of the way, you say that the only reason you were friends with your ex was because of her selfishness. That wasn't the only reason, only a part of it. Yes, I agree that asking for a friendship after you dump someone is selfish. It is usually done to ease the guilt one feels for hurting their partner and to not look like the "bad guy" in the situation. It can also be done so they can still have the ex around so they won't have to miss them. They like you in some ways, just not "THAT WAY" anymore. Also you are still "there" waiting for your ex just in case they change their mind and want you back. If they don't, they still have your friendship, so it's all good for them either way. They haven't lost anything.
The other part of the reason you stayed friends with her is because YOU wanted her back, which is understandable. The reason a person who is dumped agrees to stay friends is usually because they hope that they can remind their ex of how great they are and what they are missing and get the dumper to change their mind. I speak from experience here as both the dumper and the dumpee who then attempted friendship. I had to learn the hard way that this wasn't a good idea. I wouldn't listen to others who told me not to.
We all understand that you are hurting. We all understand that you miss her and want her back and that you are frustrated. Many people come on here wanting answers how to get their ex back. There is no answer. You can't make someone feel anything for you. You can't make someone want to be with you when they don't anymore. Honestly all you can do is be your best self and try to enjoy and make the most of your life with or without this person.
After you are dumped all you can do is say to the other person, "I still love you and I want to work things out. I don't want this breakup." If they still insist on it, you have to respect their wishes and let them go. If they ask for a friendship and it is too hard for you, be honest. Tell them "It isn't the best idea to try to remain friends because I care about you as more than friends. But I would like for you to contact me if you change your mind and want to discuss getting back together." This leaves the door open for reconciliation while at the same time stops the confusing, frustrating, disappointing, and hurtful interactions that occur when you try to be just friends when you want more. Then if they don't contact you for a reconciliation, you have your answer and can still speed up the moving on process and go on with your life. You at least know that you did all you could.