Many (blind and uncaring) people think villains have no sense of fairness.
Absurd! The fools!
Fairness is extremely important to villains. Now, their sense of what is fair may not exactly conform to Mr. Terrific's, but these aren't your run-of-the-mill people. The point is, they are strongly motivated by their sense of fairness, just as we should be.
Although we ourselves need not let it become the basis for a righteous indignation that spurs us to poison an entire city's water supply in a decades-delayed reaction to a childhood incident with a squirt-gun.