What a load of crap. I "opted out" a lot at school, playing truant, tricking parents into thinking I was ill, etc to avoid things like school sports and some other events. That was because I was being horrendously bullied. I could tolerate "normal" formal lessons, particularly with strong teachers, but would be bullied (not just name calling but physical abuse, theft of property etc) whenever things were informal or with weak teachers.
I've not opted out of anything as an adult, I've been involved in amateur dramatics, lots of clubs & societies (included being a committee member, treasurer, secretary, chairman, spokesperson etc)., ran a local "save the library" campaign, given presentations to large numbers of people, ran training courses, taught at our local college of FE, successfully launched my own business including marketing events, etc.
Funny how you're less likely to be spat at, have fag ends burned on your arms, had your books stolen or pissed on, etc., outside the school environment!
I don't think people like you know just what it can be like in schools when you're the target of the humiliation and abuse. I was suicidal at school, but absolutely bloomed once I managed to escape the hell hole and the bullies.