Hmm, I guess we are living in completely different culture. But you are right in that hobby itself does not make one abnormal, usually.
Hmm, now said that, having anime as a hobby does make one seem abnormal over here. Similar for any non-mainstream games.
I mean, calculus is a thorny issue in that it is mostly necessary for engineering, but is not usef for humanities. Not teach it, and STEM people will have jump of levels going college. Teach it, and humanities people will inevitably complain.
Personally, I think it is good to teach calculus just for the technical communication aspect.