On the Shoah and the Afterlife

A couple of days ago, I was in the midst of an argument with three friends - an Atheist (J) a Muslim (H) and a Christian (E) - about G-d, religion and whatnot (for most of the argument I was more of an observer than a participator - holding neither the position of my Theist friends nor my Athiest friend - and was, if anything, arguing against everyone). There came a stage in the argument when it turned to the Afterlife. H was arguing that there would be a stage where J would realise that he was wrong, when he is presented in front of angels/jesus christ, and that he would not be judged badly for having been an atheist. J naturally argued that that was bullshit. H then called J's position pessimistic - saying that those who died in the Holocaust deserved an afterlife (the fact that both J and I are, at least technically speaking, Jewish probably informed the choice of example). This was a point that even J had to concede - he wished there was an afterlife, in order that the victims of the Shoah did not die in vain (although he went on to say that there just wasn't one). I disagreed with both of them, however, it took me a few hours to realize exactly what it is that I found not only wrong, but offensive about the suggestion.
I think that there not being an afterlife (at least not in the Heaven, everyone's in paradise lying naked with virgins feeding them grapes, sense) is extremely important for illustrating and recognizing what an extreme crime the Shoah - and, indeed, all murder - was. If there is a heaven, then the deaths of the victims of the Shoah will not only be meaningful, they will actually have been a 'good thing' (they will be in a better place). This excuses Hitler and the Germans of any real guilt - if anything, they will have been doing a public service by killing so many. The fact - as I see it - that the deaths of the Shoah were wasted life shows the monstrous nature of the crime; without that waste, no killing can be seen as an inherently bad thing. It demonstrates the extent of humanity's barbarism, or at least potential barbarism, and shows exactly what it is that we should be working against. If those who die innocent go to heaven, there is no point in preventing current or future genocides - such as Darfur. If anything, by preventing the genocide, you would actually be doing a bad thing - preventing people from reaching Paradise.
I think there is another problem with the view that, this life being temporary, the next life will be more permanent. This essentially views life as we know it as a sort of playground - it is devalued. Whatever we do in this life, there will be something else afterwards. We can bomb and rape and pillage each other to a pulp, and it will not really matter, because there's something else - something better - coming later.
I'm not saying that there definitely is no afterlife - how can anyone possibly know that?. What I am saying is that I would rather people did not try to find positive 'meaning' in horrible crimes, for which the only real 'meaning' is that they demonstrate the sort of evils we should be working against. If you consider this to be pessimistic, fine. I don't care whether you call it pessimistic, optimistic, apathetic or anything, it does not change the substance of the argument - it does not make what I have said any less relevant.