This is true especially when the app provides the button.
> In iOS, the developer is free to label the back button or to disable it entirely to remove ambiguity.
You can do what you like with Back in Android, including disable it. http://android-developers.blogspot.com/2009/12/back-and-othe...
> I would say that this is far more powerful
Even if Android restricted what you could do, it would be an apples-to-oranges comparison since an app-specific back button has no concept of 'take me to the activity that spawned me'. But in light of what I've shown it is hardly less powerful.