To answer the question, I think the one of the reasons is that there hasnt been as much objective study put into the Russian and Chinese genoicides. I think this is for very obvious reasons, in that in one case the regime that perpetrated the crimes is still in place (and happens to be the world second biggest economy), while in the other the situation is not much better. Therefore I think a lot of the numbers bandied about these days, seem to be at best speculative. (not to detract from the enormity of the slaughter)
In contrast Germany was utterly defeated, and it was in the interests of everyone, including the newly formed german republic to find out every detail of what happend. So if its been established beyond doubt that 6million Jews died then, to say otherwise can be seen as merely trying to provoke mischief.
From a catholic point of view, does anyone here not find something even more unsettling about Hitlers plans to eliminate the Jews? Something actually diabolically inspired it seems to me!
The Holy Family, the apostles, Jesus, Mary and Joseph, had they been living then would, on account of their ethnicity, been sent into the gas chambers!!!
I know Pius deserves great credit for the work he did in secretly trying to save as many as he could, but frankly, all christians, with a few exceptions should hang their head in shame for what happened.
Its something that make me think everytime. So for me this crime is unequalled.
And I hate it when people give out about foreigners or make racist remarks or spew out hatred. We have to be ever vigilent and ever charitable.