Clicky, definitely.
But, yes, I think it fair to say that some threads are. I've even found myself making those hidden reference type remarks that someone else would understand but a newcomer wouldn't. And that, for me, is the definition of cliquey.
I think it is to be expected though. CC is referred to as a community, and I think it's a virtually fair description, and in communities people tend to know each other (some on here do in the real world too) and so will make somewhat seemingly obscure references. (If that's what you mean by 'cliquey')
So, imho, it is cliquey but that's to be expected. Cut some slack. Just remember to stay (??) welcoming to people contributing for the first time.