H1-B mandates a lower than competitive wage that the recipient's get stuck in, this isn't the same situation as women / minorities gaining access to the workplace unless their access came at a mandatory much lower salary.
This is a typical bureaucrat solution. An an immigrant you dont have the power to leverage salary, so there is no chance you will get the same results as an american, adjusted for everything else. First of all, there is a legal cost of the visa, which is and will always be paid by the employee. Second, you can adjust salary in 20 ways the bureaucrat cant see: PTO, stock grants, chances of advances, bonuses, etc. And finally, if you as an employee cant go into your bosses office saying a competing company wants to pay you 20%, because you cant do that with an H1B, your long term income is also affected.