From that link:
While traditional public relations may also rely on creative presentation of the facts, "spin" often implies disingenuous, deceptive and/or highly manipulative tactics.
That is the core of my understanding of the term "spin". Every conversation has a frame of reference, a shared context within which it is communicated. Somebody has to frame that context, and I don't see anything wrong with trying to be proactive about framing the context, as long as you do so in a way that is not disingenuous, deceptive, or manipulative. Controlling the narrative is not necessarily "spin" in this sense. It may be just seeking the truth. In fact, I have a hard time finding a better description of integrity in action that doing what you explicitly said you would do. How can you get any more straightforward than that?
The fact that it was said at the start makes all of the difference. It means that anybody who got into a relationship with Amazon knew at the beginning what kind of company they would be from an investment perspective. Amazon was setting out specifically to avoid misleading or deceiving anybody.
Even the kid in your example is not putting a spin on anything. He is being transparent and honest, not disingenuous or deceptive. To work within that analogy, as a parent I would have said that his attitude was unacceptable, because part of a parent's job is to teach and help their child learn how to make responsible choices. I would encourage the child that I think they can excel at both and that I won't accept a cop-out. If they really couldn't do both, then I would tell them I appreciate their honesty and make them drop sports. The same should be true for Amazon. If people really had a problem with Amazon's approach, they should not have bought stock in the first place, after Amazon told them plainly how they were going to operate.
That's exactly the point: the parent knows ahead of time and can make a decision with full and accurate knowledge of the situation. People knew up front that Amazon would continue to invest the profits back into the business. If people still choose to invest, they have no right to claim they were deceived or manipulated, because Amazon was clear from the beginning. How is that "disingenuous, deceptive, or manipulative?"