They have to charge people for being single

Online?
BEcause this all costs money:
- server space online
- the URL - domain name
- dating site software, and the good ones aren't cheap
- possible extra gadgets needed for a dating site
- a team who keeps an eye on it and/or hand-checks each new profile before activating, and deals with problems.
- tech-people to keep the site software updated and/or work out problems
- Payment software so ppl can use creditcard PayPal and so on
- people also like to eat & pay the rent, so they need to make money by offering it
- there's taxes to be paid
- bookkeeper needs payment and aren't cheap

Quite naive to think having a website can be done for free.
I have a wordpress site for my practice, for free still, but if I really want to get going it's going to cost me too. Meaning I have to MAKE money to cover those costs.

That statement makes no sense.

Ive been talking for free on this site for eons..

We do pay a single tax when we file taxes as "single, no dependents"

Same reason you can't get covfefe for free I guess
Fortunately POF does allow us to talk to each other for free here and directly through our profiles

Not sure what you're talking about.
Are you talking about online dating sites that charge for contact?
Might as well ask why telephone companies exist, why charge you to talk to your mother, even the government gets money from your phone bill. The government charges you for having a mother!

Or are you talking about going up to women in public and they refuse to talk to you unless you pay them?
Then you might just be talking to prostitutes.
...You probably want to stay away from them.

What in the holy Hell, are you talking about?

There is no charge to post in the forums.
There is no charge to send, or receive, emails
on mingle2.

maybe it's about the mobile/internet bill. lol