The Flash industry suffers the same curse. I can and do remove games and even entire accounts from my distribution feed. One thing I did do to mitigate it is to let individual people have their own personal listings so people can still get their games if they're explicitly looking for them.

Ultimately you have to just man up, ignore the details and don't even bother telling them why they're rejected - that sucks for the developer but it'll sap your resources and you'll get stuck arguing about it. Just send a nice, generic, neutral message:

"Your game has been declined because it does not meet our quality standards. Please review them at x and remember to polish your game until it shines."

If you want to be extra nice link to them some resources on the importance of polish.