Google, on the other hand, has done a lot for open standards and interoperability.
Is it unreasonable for people to flip out on Inbox while it's still very much in beta? Sure. If it's a real beta. Gmail was in beta for what, 5 years?
Does Google have any obligation -- moral or otherwise -- to make Inbox work cross-browser? None whatsoever.
But them not doing so would constitute a break from past policy which is something that people are worried about.