Remember people do not like change. People are superficial and vain, and thus react more loudly to things they can’t avoid seeing. The changes being made in OS 7 are easy to see, and thus the reaction will be loud.
Facebook just rolled out Graph Search for most profiles. One of my friends — who happens to be more tech-savvy than most — reacted with the typical annoyance at a third party for moving things around.
Another friend of mine was irritated when Apple joined the rest of the browsers by unifying the URL and search fields in Safari 5. She’s proficient with technology, but wasn’t happy with being coaxed to accommodate change.
These are relatively minor changes. Housman is right: this is going to be a massive shift for a lot of people who are not ready for it. I’m bracing for the inevitable emails, text messages, and phone calls from those struggling to adapt. But it’s also important to remember that none of these people have to update. If you like iOS 6, you are free to keep using it.