At some events (especially smaller ones), "parties" can seem to be at the expense of things like BoFs (as he mentions), lightning talks, hackathons, etc, and when you have so much talent all in one place, it seems a shame to waste opportunities for it to come together productively.
Some of my best conference moments have been sitting around with 10-20 people in hotel lobbies talking or in empty conference rooms coding. The worst have been crammed into a bar and having to shout at strangers. As the author suggests, let the partiers party, but give some space to the squares too ;-)