It's easy to say what is basically a glorified "Yes Socrates" and get away with not going into detail. It's harder to get away with that if you're contradicting.
Keep in mind that the problem with contemporary academic philosophy is not that it is insufficiently tolerant of dissent. The field practically self-defines as an unresolvable argument and the archetypal intro to philosophy curriculum involves learning and analyzing the debates between philosophers who disagree with each other about the most fundamental issues one can disagree about. Students are usually graded on 1) how well they learned the philosophies they studies and 2) their ability to put forward interesting thoughts of their own on the subjects dis...
Link.
Given the positive reactions, I think the professor seeded them with a positive impression of the site's content.