@LukeAlmighty compare Muslims travelling to the United Kingdom (no longer really a Christian nation) to the numbers of non-Muslims from outside Europe doing the same.
You'll find that Muslims are a fractional minority in comparison to other groups (Africans, Indians, Chinese etc..).
You'll also find that most sexual crimes are in fact not committed by Muslims (even when taking into account their minority status, they are underrepresented, at least in the UK from what I've studied).
Indeed, in many or most cases, the Muslims are refugees, so it's not like they're going there only because of "sex-tourism".