How can companies that claim to support equity and equality justify refusal of pay transparency?

I'm working at a company that loves to brag about how much it supports fairness and equity in both opportunity and outcome, and yet it does stack ranking and is very secretive about its pay structure and individual salaries, raises, and bonuses. Studies have shown that pay equality is maximized and bias in salary is minimized when wages are transparent. I think this is a case of the company talking the talk but not walking the walk.