I would take a guess that it's because it's not a proxy. I would disallow it for the captcha inplace of a browse bar alone but the captcha doesn't work anyway. It's just a page full of advertisments, it doesn't have any practical use. You need to have a proper working web proxy site to be listed on a proxy listing site. It looks like a spammer site to me, that's why it would be deleted. Personally I'd block your IP for submitting a spam site like that.