It's more that to many men from hardline Muslim countries, the "west" is seen a bit in the way that the English viewed France and Italy at one point in history when those were wild, liberated places by comparison. It may be that they can tell, but there's an extent to which it doesn't actually matter - they leave those countries really horny. And they also have rather different ideas of beauty, in a certain way - the notion we have of "passing" and attractiveness on 4Chan nowadays is actually insanely nitpicky stuff that gets down to minute details in still photographs judged by chronic masturbators. People who don't look at this stuff all day, don't masturbate constantly - for the most part, they can't tell.
That said, the pederasty thing is true and still goes on in suppressed forms in those countries themselves - something which ties into both ancient (probably pre-Islamic) customs and the puritan attitudes of the religion towards women - pretty boys still get harassed sexually from time to time. And so this masculinity and this idealization (and degradation, to an extent) of feminine males as females carries over to the west - both for yer fem twink types and legit trans types.
Iran's stance on transsexuals actually makes a lot of sense and is really less progressive than it is a religiously/culturally defined doctrine itself - IE its application to homosexuals as well as transtypes. I won't call the Quran a pacifist book, but it's really probably the less orthodox types who emerged post-Wahhab that go out of their way to interpret every application of Sharia as "kill! kill! kill!" with no in-betweens.