Nisan's description sounds more like elementary school or high school than college to me. That said, the comments also looked more like something that I'd have expected from high schoolers than college students...
Well, this is an introductory class, so a lot of the students probably started their first semester of college this month. That said, I've done peer editing for graduating seniors whose work I would have been ashamed to hand in in middle school.
Link.
Given the positive reactions, I think the professor seeded them with a positive impression of the site's content.