"Don't have parties at your confs! You're not being serious enough!"
I sometimes skip the parties at confs, but I sometimes go, and I've been to a few which were great. I think attempting to come up with some kind of Canonical Seriousness Level for all developer gatherings is doomed anyway. This is a matter of personal taste.
All you can do as a conf organizer is decide what kind of conf you want to run, and make sure people know before they buy their tickets. Or, if you're running a very large conf, set up loud options and quiet options.
There's also a flaw in his argument here, one which I hope is not significant:
"It's easier for overworked conference organizers to arrange a party than other evening activities which actually require planning."
On its own, this sentence is so dementedly off-target that it initially made me wonder what other wildly inaccurate assumptions he might be making. However, later in the blog post, it turns out that he might mean it's easier because all you do is hand it off to some company who wants to organize the party for you.
Of course, not doing anything is easier than doing something. Can't argue with that. However, if he really thinks parties require no planning, he either has no experience throwing parties, or the parties he throws are not good.