Yes, it happened, no doubt about that. But Norman Finkelstein has written a rather intersesting book on how the historical fact of the holocaust (which as someone pointed out, included thousands upon thousands of gypsies, communists, gays, the mentally deficient etc., etc., plus large numbers of Slavic peoples: the SS burnt down some 600 villages in Byleorussia alone) has been 'hijacked' (I can't think of a better word) and re-cast as a solely Jewish tragedy and as a unique tragedy that surpasses all analysis etc., That's not to say all Jewish people have bought into this (Norman is Jewish himself) The book is called "The Holocaust Industry" and Norman accuses certain segments of America's Jewish elite (in particular) of appropriating the holocaust for their own ends, political and financial, but also to deflect any criticism of Israeli policy through charges of anti-semitism. He suggests that such people are doing the memory of the holocaust victims a major disfavour.

You're right about genocide - it's a horrible thing, and let's hope we can all do our bit in whatever way we can to stamp it out whoever's doing it.