Are you certain you're not thinking only of the UK, and recent prosecuted cases? I rather think you must be. I've never heard that Pakistani men run, for example, the child grooming rings in Russia and Thailand, which are two of the largest exporters of trafficked children from what I understand.
I would point out, too, that the officer saying his investigation was hampered by fear of looking racist may well be true and is certainly upsetting, but doesn't actually prove that OMC's statement is true.
However, I'm letting myself get sidetracked.
The statements are not the same kind of statement, are they?
'Men rape' is a statement that makes the most general claim possible under UK law. It has nothing whatsoever to do with recent cases, and the only thing that would make it an invalid statement would be if the law changed.
'Pakistani men groom children' is not the same kind of statement, because 'grooming children' is not something only Pakistani men can do (unless you're a monumental racist which no-one on this thread is).
Right?
This point's been gone over on this thread already.