I will agree that you could say that, at $5, he's ripping people off by taking advantage of people who are desperate for even one minute of human interaction. If he priced it at $1, would he still be unethical and exploitative? Does everything have to be free? At even that price, is it still a ripoff? For me, the answer would be determined by the value of his feedback to people.
I will answer this question for only slightly less than $600/hr. :)
Drop me your twitter, I'll add it to the website as a testimonial tomorrow. (No joke)
It sounds more mindful and intentional than ads at least.