Damn, give GitHub a break, and judge the team by their product. They're tame compared to the yuppies in most industries.
That's exactly what their customer was doing. The customer complained about, "frequent outages, slow queues, occasional inability to push/pull, frequent breakage after code pushes, etc." It seems that the customer perceived the blog posts about drinking events as adding insult to injury (i.e. not only is the service problematic, but they're partying instead of fixing things before they become problems for end users).
Managing public perception of your company is important. The team probably needs to spend more time highlighting all their hard work, and less time comparatively highlighting the parties.
I'm aware that investment bankers (or, the people who were formerly investment bankers, before the financial crisis made all the investment banks convert into normal banks) are fast and loose with money, and drinks, and cocaine, and women and so on. I know, because I went to college with a number of them, and have been to some pretty awesome bachelor's parties up in NYC.
But Fidelity doesn't blog about their parties. Their public face is a man or woman in a suit with a briefcase and a Bloomberg terminal. Same with my 3-4 friends working at Accenture. I know they party hard because we went to college together. But they're not blogging about it, or sending out notes about it on their weekly email updates. They know how to manage their public image in a way that doesn't upset their customers. I know techies are allergic to suits, but there's something to be said for getting your customers to automatically give you the benefit of the doubt.
Taking the time to single their comment out and write several paragraphs on why 'it's totally justified to blog about partying' and why 'partying and service problems are totally unconnected phenomena because we work our asses off' seems dismissive not understanding.
The bottom line is that the blog post doesn't do anything to resolve the commenter's complaints. It's really just a long excuse, and not likely to persuade someone who begins from the premise of being dissatisfied with the level of service already being provided.
So, my impression is that since you're providing an excuse rather than a solution, you ultimately are willing to say, "we're okay with losing a customer or two in order to continue blogging about our events where we drink with customers, we'll make up the loss by attracting more customers with the parties." That's a valid business decision to make. But there may be a low cost way of managing your public image such that you can continue to have customer development parties with drinking and also keep frustrated customers.
The public image of a company is significant, and acts that some wouldn't notice can rub others the wrong way. Seems like the GitHub people don't care if a few of their customers move to other services that don't talk up their parties where they drink a lot. To each their own.