It would be both the parents and the doctors. The schools are the ones who had the machines installed in the first place and the students are the ones who take the most kick out of it.
Doctors, as we know, are experts in health and living conditions, which means that they know it’s a health risk for those who tend to consume sodas more often then they should.
Parents only want the best for their children and soda/pop are considered bad for the digestive system if consumed in massive amounts. Because parents don’t have complete control on their children at school, the freedom of course the child has gets exploited.
Hope this helped!