They are not running those sites because they are idiots that deserve to be ddos'ed.
Someone is selling a package that allows you to run you own site with the game, if he sold a few dozen you're going to see many of those sites of course.
https://bitcointalksearch.org/topic/run-your-own-bitcoin-gem-144335
Doesn't invaliditifyiy my point. Copycat sites are incredibly annoying with the aggressive marketing. There was a time at the end of march when nearly every second thread here was about another stupid bitcoindiamond or bitcoinruby or bitcoinwafflewithcherriesandcream.