The concentration camps did exist and the Nazis brutally murdeded 6 million Jewish women, children and men as well as gypsies, dissidents and the mentally disabled. You can go to the sites of these camps and you can see the memorials and you can see the gas chambers. These people did not die of cholera.

You may hate the Israelis, you may hate Israel and its treatment of Palestinians but in no way does this negate the holocaust. The holocaust happened. Accept it and do your best to ensure that it never happens again, to any group.  

A man can be happy with any woman, as long as he does not love her. Oscar Wilde