I'm always puzzled by this kind of thing.
For one, surely it's not difficult to logout and simply not ever log in again? So why people make a point of starting a thread to announce that they don't want to talk to anyone anymore escapes me. Not exactly the most efficient way to contact a mod, either. But it's really common thing for people to do.
Second, what's happened? One or two people vocally disagree with a person on one or two points, so their reaction is abandon the whole community? Doesn't seem logical to me, but again, seemingly quite common.
Or a person comes here imagining themselves to be a great teacher and full of profound, unassailable thoughts. They meet criticism and aren't universally hailed and celebrated, so they make a show of wiping the dust off their feet and publicly announce their departure. This doesn't make sense to me either, if you're sure of your convictions can't they stand up to dissection? That's what a discussion board does. Or if you're really a deep and critical thinker, why wouldn't you welcome critique and challenges to your views? But this is very common too.
I don't know which if any of these brief descriptions OP falls under. None of them make sense to me.
I guess people expect the experience of chatting with Christians from all over the world and from all kinds of backgrounds and viewpoints to be something quite different than what it is.