On the TV Tropes wiki there are multiple community subdivisions, and with the exception of a few individuals, the vast majority of tropers only bother trying to interact on a single plane. During the time period preceding the creation of the first incarnation of Trope Repair Shop, there were four such communities- YKTTW, the discussion pages, the troper IRC chat, and the Talk namespace, the function of which was largely assimilated into the forums.
Bear in mind these are just the ones I can remember, and I am understating just how many sub-divisions can exist in any individual partition. A person who posts in one section of the forums has no trouble ignoring other section- someone who just likes to post about random things in their life does not necessarily want to discuss wiki infrastructure. The same is true of discussion pages- literally every page on the wiki has a discussion page. A troper who is a common fixture on trope pages that deal with gender politics has no guarantee of appearing to mull over the issues of organization on index discussion pages.
The best way to get across the sheer broadness of this is to use the metaphor of a television crossovers. Note that this is unrelated to TV Tropes The TV Show, which is a very different idea that was developed much later:
One day, a dedicated group of people started a show called TV Tropes. TV Tropes (TVT) discussed tropes and how they are used to create meaning in fiction. The TV Show was so popular, that a spin-off was created called TV Tropes Discussion (TTVD), where people talked about the episodes they saw and argued about how to improve them. Sometimes the people from TVTD would guest star on TVT, and helped the episodes move in new, interesting directions. Another spin-off was created called You Know That Thing Where (YKTTW), where fans of TVT would get together and write new episodes for it. TVTD proved so popular that it got a spin-off called FORA, which was like TVTD but talked about entire seasons of TVT instead of individual episodes. Another spin-off called Internet Relay Chat (IRC), was the same thing as TVTD and FORA except that it was broadcast live.
All of these shows are related to one another in that they share the same universe, what with them all being spin-offs. At any time, a character from one of these shows could visit another show. Operating word being "could'. Let's take Detective John Munch as a parallel example. Technically, he could appear in any episode of Law and Order and plenty of other shows aside because he's a character in the interconnected universe. But he doesn't because John Munch solves cases for the Special Victims Unit. If he randomly walked into everybody's show, he wouldn't have any time for his own projects and he would ultimately just be a cameo appearance in everyone else's larger plots.
TV Tropes works the same way. Everyone is free to leave their comfort zone, but by doing this they run the risk of coming to a part of the wiki where they are always seen as the ephemeral "new guy", and thus their opinion loses value. Thus, you only "cross over" if your own priorities strongly intersect those of another show, to the point that you're sure your opinion will be given significant weight because hey, your argument is the correct one, and your role on the other show is such that you have credibility in this new matter.
This is just the simple psychology of why there's little inter-wiki interaction. It's not hostility on anyone's part, but rather an urge for specialization and credibility. It can, of course, go in that direction. Remember that just because characters from different versions of Law and Order exist in the same universe doesn't mean they have any idea who each other are. If a character from Cut List (CL) wipes out an entire episode of TVT from existence, characters from TVT will be understandably alarmed provided they do not know what CL is or what it's about. This is the source of most relevant wiki conflict- ignorance about what's going on and a general inability to find out. The funny thing is, that when you consider the efforts waged to create a centralized trope repair apparatus, you'd think complaints about renames would become less prominent. But it turned out that there was a great deal more complexity involved with Interwiki Interaction than we had ever imagined.