[jmromer]

> Well, dude, no, actually you can overdress for an interview and you just did.

I can think of two reasons why someone would dress up for a dressed-down interview:

(1) They don't yet understand the social terrain they've entered well enough (particularly salient: people with class/cultural backgrounds underrepresented in tech).

(2) They're conscientious enough to go through the trouble of dressing well for an interview in order to signal they care about getting hired.

So that's some of what you're selecting against when you reject a candidate for failing the "go-out-for-a-beer" test: irrelevant cultural differences and conscientiousness. Bizarre.