The irony is that he says that immediately after "Selling on Craigslist sucks, it’s time consuming and you have to deal with flaky people that just want a deal.

The irony is that he says that immediately after "Selling on Craigslist sucks, it’s time consuming and you have to deal with flaky people that just want a deal." He's recommending exactly the behavior that makes Craigslist suck.