Actually, the phrase "never again" in its most common usage specifically refers to the shoah, otherwise known as the holocaust of the Jews. You can find many ways to say you are against genocide, but most people use this specific phrase when referring to the Nazi extermination of Jews. You can use it anyway you want to of course, but this is what people generally associate it with, the attempt by Hitler at Jewish extinction. Which, ironically, a good many of our islamic friends support, and regret only that Hitler wasn't able to finish the job.
YOU are turning into a monster if you support persecution of people based solely on their religion.