So, the way to look at it is, if there are quite a number who would deny the Jewish Holocaust despite the indisputable crush of evidence that confirms it, then it's hardly surprising that there are also those who would deny the Nazi persecution of gays that was on a far lesser scale (although still well-documented). It's usually an exercise in futility to argue with someone like that, in either case.
Thank you for the kind warning. Since I did not know that the holocaust on homosexuals is used for political propaganda I originally thought that this man got simply the wrong information. I will not waste my time on this any longer. :-)