That's actually why people ARE up in arms. This is not the way the Nexus program works. Should work. Ever has worked, by your own admission. The excuse that I can flash the factory image is also not valid. It's not the same as an OTA, and it's not meant to be. AND the excuse that it's hard to code for and it takes time is not valid. Google makes the OS! If it's hard for them to code for, we're all screwed anyway. If I'm going to accept that they're having that much difficulty in getting this ready for a phone they designed and released for their own developer program, then I'm going to have to lose an awful lot of confidence in Google.
There's also the complete lack of communication. "A few weeks" and "soon" are meaningless. I think the main reason this causes so many of us to get upset is because we bought this phone because we trust and appreciate Google above and beyond the level of the average Android user. To think that Google is having so much of a hard time getting this ready that it's taken them weeks after the launch worries us. To think that they're possibly making these decisions (delayed launch, Nexus 5 exclusive components, etc) in an effort to sell more product worries us. And to think that Google is so incapable of communication that they've left their most loyal fans in the dark worries us.
It's not about the update, it's not about greed, it's not about being whiney or childish. It's about faith in a platform and a company and seeing that faith eroding away.