It could just be my impression but my sense is that there is a much larger group of non-ac fans than academics in fandom, which would suggest it's generally non-ac norms which guide interaction and discussion. I also think some fandoms welcome that type of discussion more than others. For example the Whedon fandoms were rife with meta discussions as well as academic publishing. By comparison there's very little meta going on in SPN, a handful of people who do it and one community devoted to it. And that's just anything meta-related at all, not necessarily deep thinky stuff. I also haven't seen more than a few pieces of meta looking at fan works, which is what one of the posts starting this discussion was focusing on.
In fact it seems this started with a few people having unfortunate experiences with rude strangers and then generalizing those experiences to a perceived larger group. Which is human nature but bound to make people defensive.
I do understand though why people would feel excluded from academic discussions, either deliberately or accidentally. And while academic meta can be an interesting read, I personally prefer non-ac meta in most cases because it's not trying so hard. One of the things that frustrates me about academic writing in general is all the obligatory BS that has to go into it (which in academic papers also often obscures the fact that the author has a relatively simple point to make).