I would say often times people are scared to participate in Meta discussion, or really any sort of discussion on SE, especially beta sites. I'll explain why.
I made an account awhile ago, but even before that I lurked on the site for quite a bit before I decided to create an account. Why? Because SE in general can seem a little pretentious at times. I personally don't feel that this site is, but I can sense why individuals used to a more "forum-like" environment would.
I totally understand the strict moderation though. I love it. That's what makes SE so outstanding from forums. People shouldn't be scared to participate, but they are. As a noobie I can attest that to this: Seeing all of these people with 2,000+ rep is frightening! Now, obviously the point is to learn, and answer questions but the rep is like--SUPER COOL! There is a sort of intimidation factor there. That's why (I think) the people that participate in discussions, or in Meta, usually have more rep. A guy with more rep can get away with making witty, less-than-on-topic comments.
Don't get me wrong. He isn't getting away with things because he has high reputation! In fact it's quite the opposite. It's because of the high reputation that you know he's just an active member whose giving you a hard time right now. The rep is working! It does what it is supposed to do, and does it well! But it can be a little scary to us new guys. Because we "can't get away" with as much. Which is great. We shouldn't be able to.
I'm sure this is the case on every SE though. But I feel like it's especially applicable on sites like Bitcoin.SE, Math.SE, Physics.SE, etc, because they are "mysterious." People are coming to the gods of these subjects to seek help. Where as (as you mention) RPG.SE is inherently a little more laid back.
Maybe this is all just in my head ;) I don't know.
Basically, I don't think it's anything the community can do, or the moderators. I think it's just a simple fact of having a lot, in fact of majority, of traffic from less-than-experts, talking to "experts." :)