I read it thoroughly. Ask yourself two questions. I) if your company discriminates or exploits its workforce you've got bigger problems than set time vs unlimited. II) it confuses causation. Companies with set time off will still discriminate against employees if that's their DNA. So your back at "hey If my company gives unlimited time off and I still feel uncomfortable maybe I need to make a change" vs going on and on with ever more tweaks.
Discrimination can happen unintentionally, and it doesn't have to be limited to specific groups of people. A manager could have a rough month due to some family issues, and end up turning down more vacation requests during that month. That sort of thing. If you have a set number of vacation days, it becomes a lot harder to unintentionally discriminate, and a lot easier to notice intentional discrimination.
