Holocaust denial

I have been reading a lot of stuff recently, some of which has disturbed me.  There are a lot of people out there who say the Holocaust, that horrible time in history they taught us about in school never really happened the way they say it did. 

They cite how there's no way camps like auschewits(sp?) had the capacity to eliminate as many people as they said were held there.  They talk about how zyklon-b wasn't really powerful enough to kill anyone, and those showers apparently outfitted with this chemical were actually used for a delousing procedure.  They talk about how it doesn't make any sense to trick people into going to their death when you've already got them in your custody.

I don't know man; holocaust deniers seem to have information to back them up, all kinds of evidence, to which the holocaust sympathizers only have name calling and questioning the motives of those who deny it.  I am someone who really would like to believe that the holocaust happened, if only so that I can believe there isn't a vast conspiracy behind it.  So, any holocaust sympathizers with a good rebuttal to what they're saying?

>>16

Source? 

Most of them were not fit to work, but were still kept in concentration camps, especially females, elderly, young, and the weak/malnourished.  Only a small number were in actual labor, which was mostly construction of new buildings, and even that wasn't a great benefit to Germany during the war.  Jews were told they would be forced to work in labor camps, but most were not made to work because they were unfit.  Any benefit to Germany was negligible.