Labor laws in the US are designed for companies to skirt around the spirit of the law to satisfy the letter of the law. Probably to prevent rioting in the street from making people realize they haven't won the change they thought. Case in point, certain benefits that kick in at 40 hours to you know help people out.

Companies responded by saying awe shucks, guess we will only schedule you 39 hours and if you want more you have to work another job. Oh and the law only cares about hours done at one job so doesn't matter if you are working 120 hour weeks you only get part time benefits.