Of course, we've had this discussion, or others like it, before. And there will always be differences of opinion as to what constitutes "prog-rock" and, by extension, which bands/artists deserve to be called "prog" and thus included on the site.
Personally, I feel that there are quite a few artists that don't belong here, and many that are not here that do belong. For example, although I love the music they make, most of the "fusion" bands (especially the ones that have heavy influences from jazz) don't truly belong on a "prog-rock" site. Nor do I think that artists who happened to be in prog bands should necessarily have their post-band solo efforts here, if they are not truly "prog-rock" (I am thinking here of Bruford, Collins (Brand X), and others).
However, thr webmasters make the final decisions as to what bands are included on the site (not even an admin member like me has that power...). In this regard, agree or disagree, I respect the prerogative of the webmasters to include - or exclude - any bands they feel belong (or don't belong) on the site.
Peace.