Maybe people realise they are extremely unlikely to persuade anyone here of their views? The format here is debate rather than chat, so in a way a battle is always being waged. Some people understandably get sick of war.
I'm still feeling my way around. Trying to work out what to do when I get piled on for the upteenth time because so many people here disagree with what I'm saying. I was pretty discouraged last time and I only ended up back here because I was cribbing info for a debate with creationists. I slipped into posting again, and inevitably have ended up in convoluted arguments with the exact same people I was seeing on thread after thread last time.
Things really do go in circles here don't they. At least the people here have brains, so they tend to be interesting to talk to.