I think young adults oftentimes mature at a later age nowadays. A 17 year old nowadays may really need safe spaces and may be very traumatized from being confronted by provocative ideas, just as a child would be. It's not really fair to put the burden on the child to simply not be affected; it is the responsibility of the parents and university to teach them how to handle emotions and disagree without shutting down. (I'm not refuting anything you said btw. )