Uggg! I hate "pay to play"! My husband is an artist and encounters this all the time too. It's pervasive in creative industries. It's sickening how these types of "outfits" take advantage of the hopes and dreams of aspiring writers, artists, etc for the sake of money.
Personally, I refuse to pay, aside from my $5/month here which everybody pays to be part of the MPP. My work will stand and be published on it's own merit or not, it's that simple.
Loved your article.