We've been and continue to be hit by spammers. Which is why all membership requests to the MRG are being screened by the administrators. Because of the continuing spammer hits, we are being a bit overzealous with rejections.
If you've been rejected and are not a spammer, please try again, but try and choose a username which doesn't look like random keystrokes. Using a different e-mail as well *may* help.