but there's a difference between saying "The Muslims are clearly raping children, they're muslims after all

They are predominantly muslim though.

And in the other cases, where the men are not from pakistani background, when they're north african or middle eastern, it's the fact that they're muslim that is the common theme.

Think about it, imagine you did some academic research, let's say it's completely unrelated to this. Let's imagine it's a piece of scientific research. And you found a pattern as strong as what we're seeing here in hundreds and hundreds of cases.

If you didn't mention it would your research be taken at all seriously? Or would your peers say "hold on a minute, are you daft?"