You should channel these feelings into your writing. I mean, really! I think it is actually a GOOD thing for you to feel so involved in this. Didn't a poet say that "poetry is bleeding from a wound?"
I can relate to the OP's righteous indignation of the Holocaust deniers. There are people who actively deny that men landed on the Moon, but even so, there are fewer of them than the Holocaust deniers, and those denying the Moon landings aren't dismissing the deaths of millions.I wonder if you are really getting choked up, or actually very very angry. Every time you have posted in this thread about why you need to write this story, you couple it with a tale of someone denying the Holocaust. It sounds to me that you want to write about the Holocaust so that what happened is never forgotten, so that the ignorant will realise what fools they are.
I wonder if this anger coupled with the sadness of the truth makes it impossible for you to write. People can write through tears, but it is MUCH harder to write through rage. Maybe instead of writing this book for the ignorant fools out there (who, let's be honest, will always exist. I mean you wouldn't be the first person to write a book about the Holocaust, nor the last . . . these people enjoy being ignorant), write it in memory of those who died. And also write it to tell a good story. That might sound horrible considering the subject matter, but go watch Schindler's List again. The reason it works so well as a film is that it is first and foremost a good story. The characters are interesting, heck there is even a sense of humour. Tell your story about the characters in it, not about the subject matter. Tell your story with a view to the enduring human spirit, not the crushing evil in this world.
And forget about the losers who get off somehow in their ignorance. Try to move the anger to the side. They aren't worth the energy.