While they may not seem vastly different at face, they are not as similar as you seem to think they are.
What do you expect? How different do you expect maps and calendars to be? I don't see how comparing the simple, stock applications is a good way to decide whether or not operating systems are "extremely similar."
The stability of an OS, how extensive personalization options are, and the ability to tinker seem like much more than "simple differences" to me.
I can see how, to the average end user, they look and seem very, very similar(especially with iOS 7, which I have not used a whole lot, but have been told functions and looks a lot more like Android's UI), but that doesn't mean they are. They are entirely different operating systems that have different software offered, features, and communities.
As a sidenote, it's not very compelling when you say "only (derogative word here) will say something contradictory to what I think."