Has anyone read Axelrod's The Emergence of Cooperation? Looking at the above quote with that book in mind, I'd say that PG is trying his best to establish his reputation as a bully. Yes, probably all founders would be stupid to pass up on his offer, no matter how low. However, given that, at the offer stage, he has already spent some time (and money) for the interview, he's partially invested in the startup. Thus, he would also be "stupid" to reject a counteroffer that was somewhat more favorable to the founders. But then he would ruin his reputation as a bully, and open the door for more negociations. So he won't negociate at all. It's his best strategy.
It's not necessarily a bad thing for us, as long as he still makes a fair offer, but the way he says it makes me cringe. He's using the applicant's ego. Who here would like to fail PG's IQ test?