You mean intentionally alienating people and hiding content behind elitism is resulting in low activity? I'm shocked.
Well, sometimes people who are collaborating on a project want to work out the details and share things with each other without having everyone else in the world chime in on it or steal their content. There's nothing unusual about that. And it's not like you have to be some ASM wizard or anything to be given access. In my case I just made some posts/screenshots of things I had done with Hyrule Magic and 2 or 3 custom sprites and I was in. You basically just have to show that you are willing to take the time to learn to use HM and make use of the resources that are available rather than relying on everyone else for every little thing like so many of the people who show up and then disappear two weeks later never to be seen again. And as long as no one is rude and completely incompetent we will give them all the help they need.
It's also worth noting that Zeldix originally started because people who were working on a hack together needed a better way than emails to communicate, share and organize their work. I think it was completely private at that point. Hell, when I first signed up over there it was invite only. I think it may have been Puzzledude that invited me after seeing some of my screenshots here. Now anyone can join though and there's nothing stopping anyone from getting into the "club" but themselves. That's not elitism, it's a minimal set of standards that really only gives you access to the private project threads (there are also project threads that are available to everyone) where people work on and show their progress to each other.
EDIT: If you need any more convincing, go over to zeldix.net and see how many patches, docs, tools, etc. are available even without an account.