When I was about 30, I lost the ability to metabolize alcohol. I can have the equivalent of a shot glass full of beer or a teaspoon of wine, but any more than that makes me dizzy and nauseated.
I’ve been in workplace cultures where it was no big deal, in ones where it was occasionally awkward, and in ones where it was a distinct disadvantage. The difference lies, as you note, in how personally people take the presence of a non-drinker and how much the workplace culture centers around alcohol.
People who are, like your boss, offended by the presence of a non-drinker are very much like the heterosexual who is offended and threatened by the presence of somebody who is homo- or bisexual, or the rabid music fan who attacks their idol’s perceived rivals and the rival’s fans. “How can somebody be so different from me in an area that’s so important to me?”