I don't mind going out for happy hour once in a while, I enjoy it, and would never give anyone a hard time that was drinking, say a diet-coke with lime. The writer seems a little sensitive to socializing/drinking though. Perhaps he doesn't realize young people like to "rib" those who are a bit different... I don't think they mean any real harm, they just lack perspective that comes over time. I've learned to ignore people's dumb comments, as I've made quite a few myself--hopefully they are decreasing over time.
However, in agreement I've noticed that a lot of company/startup "culture" tends to exclude anyone not a late-twenties white|asian male with skinny jeans. Here's a few job pages I've looked at recently:
https://www.planet.com/assets/themes/planet/images/team/taho...
Look at some of these photos, and struggle to find a team member from the majority of the population who is homely, or chubby, or female, or $other_minority, over thirty, or god-forbid over forty.
No wonder it is so hard to find people when you exclude 90% of the population.