I tried to come up with some snappy title for this but nothing seemed to fit. So well- (or badly, depending on pov) timed as to seem almost a publicity stunt...
I rather suspect Imperial has a higher-than-average population of students of British-Asian or Asian origin. Not surprising if so given that its specialisations are medicine and engineering -both of which remain, I think (I have no source for this, it's merely an impression), very popular professions among Asian/British-Asian people.
Frankly I reckon if they're going to insist on a dress code it ought to be sub-fusc. Actually, I wonder what the rules are about sub-fusc and ethnic or religiously motivated dress...