One could be tempted to justify this (as many in the Austrian economics camp do) on moral grounds. In the latest post, we've seen that this objection seems to be irrelevant.
Two new objections are possible now. What if Fred was an original capital subscriber? What if he contributed capital to the firm? Without his thrift there would be no Apple Inc! Surely he deserves a reward for that?
Or perhaps the reader would object the examples used on a different ground. Small shareholders don't control the firm. Big shareholders do; their momentous decisions on crucial matters, that's what creates wealth. (h/t Tao Jonesing, and comments here)
We'll consider the second objection (the decisions) in this post, leaving the capital contribution objection for a subsequent post.
Let's consider this objection carefully. The point is not that shareholders in general deserve their gains (small shareholders, for one, don't deserve them), but that some shareholders (the big ones) do.
In other words, there is a difference between small and large shareholders, justifying big shareholders' gains. Namely, large shareholders contribute something (i.e. their decisions); small ones don't contribute anything.
This means that, if there is a justification for these gains big shareholders get, it must be these momentous decisions. Thus, anyone making those decisions would deserve those gains, perhaps proportionally to the decision's importance.
This introduces several questions, which we'll leave aside, for brevity's sake. 
Here we'll settle these questions in an arbitrary manner: big decisions are those made solely by the board of directors and senior management. We'll reconsider the whole issue later.
In their capacity as directors or managers, these individuals are in reality the owners' agents, legally obliged to act on the owners' behalf. And they are paid for the work they do in that capacity: salaries, directors' fees. Observe carefully: they work and get paid for it (by the way, extremely well paid), just like any other worker.
In other words, managers and directors are legitimately entitled to a compensation for the services they render to the firm. One might question, however, the magnitude of the compensation.
As it happens, managers and directors are sometimes owners. But if these manager/owners get salaries and directors' fees for the work they do as managers and directors, what, then, justifies their keeping profits in addition to their salaries/fees?
For the moment, I'll advance the two possible answers that seem to be left:
- What explains their receiving profits/dividends is their legal ownership of the firm. Exactly like individual shareholders and speculators.
- The capital contribution (which, as already said, we'll discuss in a coming post).
The crucial objection to my conclusion that profits and dividends are due only to ownership is the capital contribution, which small shareholders don't make and that large shareholders make (assuming, and only to the extent, they actually contributed something to the firm!). This explains my choice of leaving this last objection for the last post in this series.
Before closing, we should go back to the arbitrary answer given before: crucial decisions are those made solely by top managers.
If this were so, then rewards should be proportional to the decision's importance to the firm. Good decisions, leading to good outcomes, must be highly rewarded. Bad decisions, leading to poor outcomes, must not.
I don't think we need to go to great lengths to see that this is not what happens:
 For instance, everybody in a firm, from the chairman of the board, down to the receptionist and the janitor, makes decisions affecting the firm. What makes their decisions different? How do we measure a decision's importance? What is a big decision, anyway?