I don’t intend to sound anti-Semitic, and as a point of reference my fianc/e is Jewish, but I sincerely doubt that the theft of the Mezuzahs had anything in particular to do with the fact that they are Jewish symbols.
If I am wrong then I am deeply saddened, but this being my second year of living in the dorms I can tell you that if you put anything at all on your door there is a good chance it will be stolen.
Another reason I don’t believe these thefts were intentionally anti-religious is that a Mezuzah is not something the average person not of the Jewish faith would recognize as a religious icon. Had the thieves taken the Star of David off of a door it would have been a little easier to see it as anti-Semitic.
My guess is that whoever took the Mezuzahs did it for the same type of reasons that people take white boards, stickers, posters, room numbers, etc., off of people’s doors in the dorms. Whatever reasons those happen to be.