I agree that dividends are a healthier and saner way to earn money from investments. The problem is that as a little guy I have no control over whether some company makes a dividend distribution, or even whether they make a profit or not. I
can control whether I buy that stock in the first place, and control whether and when I sell that stock. Therefore to make money in this latter scenario, the stock price
must change (usually up, but if you're shorting, down can work too) in order for me to make a profit. Thus it's in my best interests for a stock's price to fluctuate, regardless of whether that fluctuation has any relationship to the fundamental health or profitability of the company. It's weird. It's dumb. But that's the way it is.
And that's just the incentive for the little guy who's an outside investor. Imagine now you're a big guy with a lot of financial clout, and inside connections, especially as far inside as being on the board or one of the executives. You not only are incented to cause distortions to the stock price, regardless of merit, but you also have greater power over the "upstream" numbers (how to define profit, when to book profits/costs, etc.) and over the media presence and general public's perception of the company. Greater potential upside plus greater power to manipulate, is a recipe for bad things.