They may be explainable but do you really want to install an app that _could_ keep track of the numbers you call and then send them back to a central server?
In this case it is the BBC, so its probably only likely that the british government, the metropolitan police or mi 5/6 would be able to convince them to do it but a whole lot of less scrupulous organisations ask for that permission.
I think Android permissions are probably the best at the moment, because they actually exist, are centrally located, and are easy to read. You won't see any certain permission detail longer than a few sentences. They also are shared, so if you have seen one permission for an app to access your contacts, it will be the same in all apps. Apple requires less permissions disclosure and they can be listed in the app store, or on the developers site.
However, ideally I would like to see the current Android permissions segmented further. Right now they act as a catch all to ensure all bases are covered. This is often way beyond what most apps need and actually use, making users second guess what they are installing (at least, they do for me).
In this case it is the BBC, so its probably only likely that the british government, the metropolitan police or mi 5/6 would be able to convince them to do it but a whole lot of less scrupulous organisations ask for that permission.