MacVim is not official and it doesn't ship with any version of OS X. It's nice that third parties have developed tools to try and bridge the gap, but it doesn't really address my original concern.

Now, the OS X Terminal (and programs run through it, including vim) does support Cmd-C (after highlighting with the mouse), Cmd-V, and Cmd-A, because the OS can treat them as raw text without the terminal knowing anything about them. It doesn't support Cmd-X, Cmd-Z, or even basic navigation keys like Home and End.

I really don't understand why neutral statements of fact get voted down. Is somebody way too emotionally invested in the discussion? Somebody reflexively downvotes anyone who makes them examine their assumptions? That dude I told off last week stalking me? Misclick? It's just weird.