You're talking rubbish. Copyright covers the entire game, not just the name, music, graphics and game play. Tris is a blatant clone / copy of Tetris end of story. You've even said it in your post, referring to it as a 'free clone' - how can a clone of something not breach copyright? You can change the graphics, music and make small variations on the game play but you're still in breach of copyright.
Sure there are loads of clones out there that the copyright owners turn a blind eye to but that doesn't mean they are legit or legal. I wouldn't be surprised if some of the more famous clones involved some form of payment to the copyright holders, ie some kind of licensing deal.
Not sure if you were around when Tetris came out but it was pretty much 100% original when it did - there wasn't anything else like it. Anyone new to the format might not think of Tetris as anything other than one of many similar games, but it isn't as its the original that everything else copied.
I don't know how anyone can view this kind of intervention as being greedy either. Games companies making versions of Tetris have to pay a lot of money in licensing fee's, why should other people profit from it without paying up?
He's lucky they're not suing him anyway, which they could even if he does take the game down - in which case he would be taken to the cleaners.