If I understand your point correctly, it can be summarized as "Applications are probably doing whatever the heck they want on iOS too, we just don't know about it." If that's not your general idea, please correct me. There are at least two problems with this statement:

1) You are contending that Apple is in an equally powerless position to prevent apps from deviating from stated purposes. Yet even the app in the anecdote you brought as an illustrative example has been removed by Apple. If any other iOS app was found to be in violation by anyone, and Apple found out about it, it could be removed immediately. In contrast, the apps tested in this research paper will likely still be in the Android marketplace one year from now, and because people don't read the news, they will likely be as popular.

2) I don't think it's really that difficult to do similar analysis on the iOS market at all. Just connect to the internet via a router with some kind of packet sniffing. Obviously, until someone actually does it, we're just guessing- you're guessing that apps on iOS are just as bad, and I'm guessing otherwise- but to blame the lack of information on iOS not being transparent enough for researchers doesn't seem accurate.