Do you not think "beating the market" is zero-sum?
No, at least not without a whole bunch of additional qualifications.
Two simple examples. Let's assume the "market" is S&P500.
Example 1: I leverage my investment 2:1 and buy and hold the market. A year passes, the market return was positive, my return was twice as big as the market return. I beat the market -- who lost?
Example 2: I do not invest and stay in cash for the whole year. The market return was positive, I underperformed the market and so lost -- who won?
1) The person who lent you the money, and who could instead have invested it the same way you did.
2) The person who bought the stock you could otherwise have bought.
Edit: Solipsist's answer is better than mine.
P/S/A: There are single sentences which can create life-changing amounts of difference.