Using this thread to recruit students makes no sense if all the criticism is believed. Helping students with their due diligence is a more rational explanation.
Or, to make the impression of helping customers with their due diligence whilst challenging them to accuse you of pretending to know more than you do.
for example
Student: "Howard, I've seen your course, but how do I know you are the real deal?
Howard: "Well, if you take a look at this thread you can see for yourself"
Student: "But Howard, most of the people in that thread are saying you don't know what your talking about and that you shouldn't be teaching a course"
Howard: "What, DashRiprock? What has he published? Does he have an option trading journal? And do you really think someone who posts so much LULZ can be taken seriously?
Student: "Well, I suppose not... but what about the others?"
Howard: "They're all the same. Anyway, if I was a conman, why would I show you that thread?
Student: "ummm...."
Howard: "Do you think I am a con man?"
Student: "No, that's not what I said"
Howard: "Good, glad we've cleared that up. Now, do you want to pay in one go or by installments?
It's a simple confidence trick, happens in sales all the time.