Answer by Prof. Dheeraj Sanghi
Because most activists on campus want others to follow the law, and keep quiet when violating the law helps us. The helper in the Institute should get minimum wage. Helper in my project, well may be. Helper at home, certainly not. (And of course, the law itself says that for the household help, no minimum wage is specified, so the activists are not violating the law in letters.) Same way, you won't find any child labour in any activity paid for by the Institute. (Or at least action will be taken, if any instance is pointed out.) But canteens is another matter. Individuals pay for the service.