And how exactly does that stop you from making a confidential complaint to the DOL where they investigate the entire business?

The DOL looks at payrolls, time records, everything, for ALL employees, not just the one making a complaint. Many times, they will even interview present and former employees during their investigation. An investigation doesn't even have to be triggered by a complaint, even though most are.

If at any time, within the previous 2 years (or 3 for a willful violation, such as intentionally not ensuring you earn at least minimum wage), it is found they have not acted in accordance with Federal labour laws, that is righted. You know that guy who quit 6 months ago? If he didn't get paid correctly, they'll make sure he gets what hes owed.

If you aren't a moron and keep it to yourself, your boss will have absolutely NO way of punishing you for it, short of picking somebody at random or firing everybody.

It's literally all on their website, which I linked above. I'm just reiterating what it says at this point.