The USA has a concept of an “exempt” and “nonexempt” worker and a series of questions that determine this status. In general, hourly workers (nonexempt) get many protections encoded into law that professionals don’t. And professionals don't want them except for a very small minority of oddballs that want to unionize.

So in essence, applying the same set of outdated rules to everyone. It even makes it hard to compete with colleagues for promotions if your hours are limited. Of course the French engineers I had lied to the government about hours worked as they wanted to maximize bonuses, stock grants, and promotions.