I think it's this: Motorola wanted to make the Razr the thinnest phone possible as a selling point, and the best way to make a thin phone with an adequate battery is to have the battery not be a removable part. All of the stuff that they have to do to make the battery removable adds thickness (or length and/or width) to the size of a phone. I think it's as simple as that. Apple has proved rather spectacularly for over a decade now that many people are fine with non-removable batteries in portable devices. Of course, there are many third-party portable charging solutions for iPhones, but most of us have access to power in our cars, or power where we live and work, to briefly charge portable devices during the day. Of course, we also always have those times when we don't, and those are the times that it's frustrating.
All that said, I have been using Android phones for 26 months now, all with phones with removable batteries, and I do have spares; do you know how many times I have swapped a nearly dead battery for one that I carried that was charged? Not once. I think that the non-removable battery thing is a way over-blown criticism, though I do realize that there are some people for whom this is required.