This community seems to be overwhelmingly about identification and trivia related to specific TV shows and movies. But there are SOME questions about movie/TV production and general questions. These seem like two completely different genres and I was surprised to find them intermixed here. As the Brits would say: "like chalk and cheese".
Well, first of all the introduction blurb of the site itself says:
Movies and TV is a question and answer site for Movie and Television enthusiasts. It's built and run by you as part of the Stack Exchange network of Q&A sites. With your help, we're working together to build a library of detailed answers to every question about Movies and Television!
While this is rather general, we can as well take a look at the help center, specifically the section that mentions what questions are on-topic here. While not being an exhaustively complete list, it mentions the larger topic areas this site engages into:
- Analysis of content or theme of all forms of Movies and TV series
- Identifying a Movie or TV series (see below for details)
- Questions about a Movie or TV show's production.
- The works of a director / an actor / a writer related to Movies & TV
Though, the gist of what this site is about is the appreciation of movies and TV-shows. This means we employ a primarily consumer-oriented viewpoint in the questions we entertain rather than a producer-orientied viewpoint.
The primary kind of questions here delve to explain and analyse the story, themes and artistic as well as technical realization of individual movies and TV-shows in a way that adds to their appreciation. And this is what the site is primarily about. While we also feature general questions about how certain things are done in producing films, to varying degrees of technicality, we still concentrate on explaining how things are done in existing works, not so much how to do it in your own stuff. The line between both can admittedly get a little blurry sometimes and it might only be a question of phrasing to which viewpoint a question adheres, but that's how it is. At the end of the day, though, the final goal still comes down to appreciating films rather than making them.
There are different ways how one could try to seperate these issues into different communities, however they have their flaws:
- Separating discussion of content, i.e. story, characters and themes from discussion of realization and production. This is often not easy to distinguish since a large part of a film's impact and expression comes from its technical and artistic realization.
- Separating The discussion of individual works from general questions about the medium. This has the same problems of not being able to discuss the realization of individual films without an understanding of how films work and are done in general as well as the unability for general discussion without the employment of individual examples.
- Separating movies from TV-shows. This has indeed been discussed during the very early days of the site, which originally started out as just Movies (with a separate proposal for a TV site). The conclusion was that the same principles that apply for films largely apply for TV-shows as well and thus merging the two is a sane approach for a shared community.
There are, however, some slightly contentious points about the site's scope that you rightfully adress in your question.
The degree as to which something is mere "trivia" rather than a genuinely interesting question adding to the appreciation of a work is to some degree a not exactly solved problem. While this site does have a close-reason for "trivia" to avoid merely replicating IMDb, it can sometimes be debatable when this is appropriate and there are discussions about that on meta. Though, it often just comes down to properly motivating your question.
As to identification questions, well, they are actually a heavily controversial topic on this site and by many users rather tolerated more than encouraged and you are not too far off in your assessment that they seem to comprise more or less their own sub-site of questions that don't really fit to the rest of the questions encouraged here. However, this is how the site historically grew into shape and they have to look back on a long history of discussion about them, which might even some day result in their abolishment. But recapping that here isn't really the scope of this question and meta is chock-full of discussions about that matter.
So the bottom line under which all those questions (apart from ID maybe) can be summarized would be something like