It's a waste of time you should be learning how to become a real writer!

(a) Why can't writing be a hobby, just like knitting, woodworking, pottery, sketching, photography, singing, playing a musical instrument, acting (seen any amateur productions?), jewelry making, sewing or cooking? What makes it so different to these other creative hobbies?
(b) Feedback is better than money. I already earn money at my paid work.

You have to think of the children!

(a) It is not my job to police children's access to the internet, that is the parents' responsibility
(b) Most fans put warnings on their adult-only stuff; that's sufficiently responsible
(c) Fanfic does not equal Porn, for goodness' sake!