The existence of Jesus could be true or not in fact but it won't change the fact that the Christians see him as a divine figure. Mohammed might or might not have lived under the circumstances we hear about but there will still be an Islam as a result. However the Holocaust is not a matter of faith. It is a matter of established fact confirmed over and over by scholars in possession of the relevant material, which is open to all of us. Doubting this event in history can only be motivated by a desire to delegitimise it and the people who suffered. You're talking about erasing the memory of an event or blurring it. Get over it, get a grip and worry about earning a living.
Firebomb thrown during demonstration in northern Israeli town of Umm al Fahm (Haaretz)
from the article: Oxford Union reportedly invited Holocaust denier Irving to speak