It's a "comedy" set partially in a death camp. I'll summarize the criticism for you:
Benigni's character acts in a way that, in reality, would get himself, his son, and his companions killed (the worst example is his "translation" of the officer's instructions), all for the sake of protecting his son from the very obvious harsh reality. Also you shouldn't make jokes in a death camp because jokes are funny and death camps are not. Or something.
I'm willing to forgive the lack of factual accuracy, as it's replaced by a very entertaining story.