It's fairly alarming to read company dictats like this one. I hate to think that anyone could have some split second change of mind about the use of a particular word and then try to force it on the rest of the culture, top-down.

Yes, there's some sense in which "user" connotes a detachment from the people who use the programs you create, but I hopefully Square isn't such a centralised culture that the CEO gets to decide on it in isolation from "the team".