My 2 cents: as much as I love nutrition as a topic, I don't think our community can handle fielding nutrition topics without a MUCH larger expert base, and I don't see that happening anytime soon.
I have a relatively large amount of lifestyle medicine training and clinical experience, but still feel an aversion to answering 99% of the nutrition questions that pop up here. I have put some thought into why that is, and think there are several themes:
Many questions have no evidence-based answers because they are too limited in scope to have ever been studied. In person I could discuss speculative risks-benefits based on what is known, but this site isn't well-suited to that at all. Speculation just doesn't fit here.
I can't cite the specific reference for all nutrition advice that I use in clinical practice off the top of my head. It's a synthesis of years of study, practice, watching clinical results, and learning from mentors. It would be one thing if it were a simple fact or clinical guideline, but nutrition is far more complex because there isn't a central set of professional standards - it's a synthesis of MANY sources, so it can be extremely time consuming and difficult to retrace those steps. For example, 1/3 of the pages of the lifestyle medicine book "How Not to Die" is just a list of reference sources. Some docs I know can do that but my brain doesn't have that kind of bibliography section. :)
I'm eternally learning, and there's a lot more I still need to know to be able to stand in a debate on nutrition against the waves of pseudomedicine in the supplement world. Some is legit, some is straight-up harmful. But scouring references for evidence to pick apart hype from solid is tedious work, and we just don't have that kind of manpower.
There is a lot that remains controversial even within the medical field on nutrition. People debate the clinical application of studies all the time - even those who have the same fundamental philosophy on nutrition debate the fine points of it. The ACLM has only recently put together a standardized curriculum, and that took them a great deal of discussion to decide what to include and what not to.
We have no obligation to be a comprehensive encyclopedia of all health topics. And we need to accept that some people WILL get upset about the fact that there's not a good place to ask their question, but we can't solve the entire worldwide shortage of health information dissemination on our own. We just don't (and won't) have the capacity to field everything out there. So being selective is a survival mechanism. Eliminating nutrition will reduce the controversial questions that no one feels like touching with a 10-foot pole, and that will reduce the burnout of the experts who we're trying to retain.
It may help to specify in the guidelines that a question has to be answerable with evidence-based information, and if a topic is too controversial to have a clear clinical consensus, it might be closed as off topic.