So if the point of this site is a sort of safe haven for non-believers, how do believers find their way here?
It is rare for believers to shwow up here. When they post, they often get blocked. If they are abusive, they get kicked off the site if a lot of people flag them.
That beign said, it appears the sie does n0to discriminate based on belief or lack of belief. If believers want to come here, they can. They just need to behave themselves and respect others.
I don’t think anyone expects anyplace on the internet to be a “safe haven“. Different people have different levels of belief in different things and click on different things for different reasons. Most agnostics are ex-theists, I am however atheist and have always been.
You'd have to ask them.
Most, I would imagine, are curious and/or think they are some sort of Truth Warrior with novel "gotcha" arguments that they plan to take us down with. A minority might be liberal theists open to interaction with at least some non-theists.