How should (inevitably hostile) discussions of the Holocaust be approached ??
Understand which part of the story is the BIG TABOO for your public/listener. Do not approach this part right away, if at all.
Understand that every important definition is like a space on a chessboard that needs to be contested, thrust into doubt. There are many relatively harmless ways to "redefine" 'Holocaust' which go along way to showing people that THIS IS AN EVOLVING STORY. Get them to say the simple phrase "The victors write the history."
Ask how many Jews survived the ghettos/camps. Very rarely will anyone want to talk about this number. (4-5 million)
Get the believers all tangled up in the earlier lies of their 'Holocaust Story,' such that they realize they actually know very little. Who was gassed, where ?? In Buchenwald, two million ?? In Dachau ?? What ?? Piles of corpses, from what ??
I like to say often :" To me it's an open question, which unfortunately cannot be openly discussed in most European countries. Why is that ?? "
Ask for some serious literary sources from experts in the field, from the last twenty years. Whenever they think they know something, point out that they "learned" that from a movie.
Consider that whatever happened to the jews, it happened in the midst of an inconceivably vast war which consumed tens upon tens of millions of innocent souls, whose fate we are curiously not so interested in.
If talking to a jew, remember that for these people there is no "objective reality" which we can agree upon; they view all stories, accounts, memories, wailings and weepings, articles in newspapers, movies,TV programs, as just ideological tools to advance their agenda.