In my only ever job interview in the US, I was told beforehand to dress casually for my visit to their office. I'd expect that kind of preparation to be routine

In my only ever job interview in the US, I was told beforehand to dress casually for my visit to their office. I'd expect that kind of preparation to be routine for professional HR people. The attitude displayed by startups seems indicative of their arrogance and overconfidence after being given money for their "great" ideas...