There are two situations for this, both are entirely mental.
For whatever reason, when writing a profile which forces you to think about the question, people come up with an age range in their mind for reasons of their own. Everyone does it, including me. So now we're ONLINE, and the age people put on their profile affects the choices of the people who see it. No matter what the pictures look like, no matter what they say about themselves in the profile text, that number will often weigh heavily on the yes or no of the viewer, based on the arbitrary judgement call they made when forced to answer the question about their age range. And all ya'll know how I am about judgement, it's not a bad thing.
There's also a difference in mindset between real life and the internet. When people look at other people on the internet, they are looking for a reason to say no. Face to face, they are looking for a reason to say yes. It's a human nature thing. I don't know why it's that way, but I've observed it over and over.
When you go to a club, meet and greet, house party, or hotel party, nobody is thinking about the AGE NUMBER. It's even considered rude to ask an age in social etiquette. So at a swinger event, the age number doesn't matter, there's a real person standing in front of you, and you are either attracted to them or not, based entirely on their appearance, mannerisms, and personality.
So if you're a person who is routinely rejected online because of your age, get your ass off the couch and go to some swinger events. Run it up the flagpole and see who salutes it. And stop pissing and whining about being rejected for your age. It gets old, and the arguments all the old rejectees make are just pathetic.