ummmm me
(I mean I hate Go but in a hypothetical world where I liked Go, me)
If I see someone wearing a political t-shirt, they're clearly virtue signaling. If I ask them about it, I might expect political slogans, but often they won't even be able to manage those slogans, much less explanation of a party platform.
If I see someone wearing a branded beer shirt, they're likely to be able to represent for their shirt-beer. Most of the time I'd only expect advertising slogans, but once in a while maybe they'll have something interesting to say. They're going to be generally more informed than the political shirt crew.
A programming language t-shirt is much more niche and advertises that the wearer has an interest in that language and wants the world to know about it. This goes far beyond the virtue signaling of the political shirt crowd. If all they can do is repeat slogans (like most of the beer-shirt-wearers), I'd be disappointed, too.
Reminds me of all the clueless people wearing Che Guevara shirts...