Did you not get that impression, or did the feeling of social support occur despite that?

It occurred despite that. You don't interact with other people, but you do meditate in the same large room, eat in the same room, and follow the same schedule. The videos at night discuss problems that most students have, which also helps build social support. Knowing that many people are going through similar difficulties is empowering.

Can you articulate what about it is difficult?

Sustained mental effort, unpleasant emotional experiences, unsavory personal realizations, and physical pain. Straight head-butting your mental habits.