Could you explain what is arrogant about it? The all caps doesn't come across as arrogant or weird to me on the blogpost.
The title of the story on HN has since been corrected to normal case.
I'm not an Uber hater, if anything I'm inclined to defend the company. But posting ALL CAPS to HN is either arrogance or carelessness or (most likely) some combination of both. I would not normally pay attention except this is a company which already has a reputation, so maybe it's actually part of the corporate culture? Or maybe I'm overthinking it.