Well, I’m not the one that actually runs the group. That group is actually by the girl that runs @ask-tinysam. I do know what happened, though.
Normally she didn’t have to worry about submissions being on topic, but there was one person submitting a lot of art that doesn’t fit into the (gt) part of supernatural gt (if you think it was you, it’s not because they don’t actually follow me). So she had to make it so submissions need to be approved. Currently she’s in school, so she doesn’t have much time to get around to running things on DA or tumblr.
I let her know your concerns!