I'm ambivalent about this. With this policy it seems like the university is admitting that it's unequipped to deal with the increase of mental issues and also unwilling to invest more resources into it. It may also be a legal precaution, i.e. if a student ctb on campus and they're afraid of being sued, although I don't know how realistic a possibility that is. I know from experience how hard it is to attend university with serious mental illness. In many cases it's a waste of a time and money. Withdrawing for a time might be a wise course of action, although Yale could make readmission less stressful.
It's a similar situation at my own university, where there's been a huge increase in demand for mental health services. They have some services in place but they are overwhelmed and of limited ability to help. Student suicides are obviously a "bad look" and the university is very hush hush about it. As a TA I received basic training in handling student mental health crises, which is no bad thing, but it shows how thin the line is stretched. It's clearly a major and growing issue (and expense) for universities these days and they are struggling to respond adequately.