I think the Muslim comment was a little misguided, but it really is hard to tell. Most will just "label" someone as a member of a particular religious order by what they wear, skin colour and native alphabet, among other things.
Also, I know Canada has heavy fines for the carrier of a passenger who does not have the correct travel documentation, so it may have been cheaper to return. Could have just got on the wrong flight, but then, who's fault would that be?
Just some thought, although, I'm not an airline pilot.