But even if they're not liable, they're still, to some extent, responsible for the students at their university. 18-22 year olds are adults, but many are still developing emotionally and have just moved from living at home and the K-12 educational model into an environment where they're expected to be independent and fully self-responsible, and the academic work is likely far harder and more stressful than anything they've ever experienced before. It's a transition period and the university is, rightly or wrongly, viewed as a pseudo-guardian during this time. If they don't provide the image of performing this role, then they'll be viewed poorly.
Edit{snip}
"Capacity" is variable. Someone may have capacity to feed themselves but not to make financial decisions. They might have capacity to give assent, but not consent, for surgery, but have capacity to give consent for other medical treatment.
When you remove capacity you should restrict that to the minimum actions you need to take to protect that person from harm.
Of course, that's all England which operates to European human rights laws which operates to international human rights treaties. Things might be different in the US.