Is it sinful to judge God or is it simply meaningless? I often hear that a man can't judge God - but never fully understood if that was because we're not one to question the superior, or if it was just something wrong to do.
For the sake of discussion, let's assume there's a deity. If so, and if that deity were incomprehensible to us, then it would be meaningless to judge it. Whether it was sinful or not would depend on whether or not that deity took offense at being judged.
Now, even if all that were indeed the case, it would still be legitimate to judge, criticize, etc. human concepts of that deity. At least that's how I see it.
As for some notion that it's wrong to question the superior, that would seem to me a weak ground upon which to base an aversion to questioning, judging, criticizing, etc.