First off, I am disappointed to see this thread, which I intended as place where we could help each other learn to use the new site has turned into a debate about gender identity on the site. Basically, the thread is now useless for what I intended. However, that is the way of forums and since I'm not in a position of authority here, I can't really change that (On my own board, I'd have moved the discussion to its own thread. I'm a bit of a cranky ape as a mod/admin).
My own view is that it should be an optional field (but wouldn't complain if it was removed). That's how I've done it on Wondercafe2, where is similarly unimportant but some people still want it as part of their identity. We've done a simple list of Male (which would include both Cis and Trans), Female (ditto), Fluid/Non-Binary, and, most importantly for this discussion, No Selection as the default. And if it is left as "No Selection" the field is removed from the profile. Even with SS's longer, more comprehensive list, adding a "No Selection" option, making it the default, and adding some code to hide the field from profiles when that is selected should not be rocket science.