This is bad for the free market and freedom of speech. I hope it gets challenged on First Amendment grounds.
In the employment world, folks use Radford and similar as guidance which of course can steer them of course from where the local talent market actually is.
This is actually illegal in many states. Workers have a legal right to discuss salaries.
>Freedom of speech pertains to legislation from congress preventing political speech.
Not correct. Free speech is about any freedom of expression, not just political speech. There is endless amounts of case law to back this up.
https://en.m.wikipedia.org/wiki/Virginia_v._Black
https://en.m.wikipedia.org/wiki/Ashcroft_v._Free_Speech_Coal...
You can find a big list of free speech cases here. Many cover non-political speech.
https://en.m.wikipedia.org/wiki/List_of_United_States_Suprem...
Freedom of speech is broader than that. Freedom of speech not only extends beyond congress (which the Supreme Court has repeatedly affirmed), it also goes beyond political speech. You have the right to espouse openly racist beliefs. You have the right to espouse religious beliefs, and beliefs on the best way to grow corn, and what the best auto maker is. These are not political opinions except to the extent that they are protected from suppression by politicians. (Alternatively you can argue that basically all speech is in some fashion political, in which case the "political" distinction is meaningless.)
While it's true that businesses can assert First Amendment rights, as with this recent Supreme Court case https://www.nytimes.com/2017/03/29/business/supreme-court-cr..., that doesn't mean that laws that make it illegal to inquire about or take into account past salary history, marital status, pregnancy status, etc. are all unconstitutional simply because spoken communication might take place during the process of flouting the law.
Or to put it another way, it's not the words, "So, are you pregnant?" themselves that are the problem. The problem is the implicit idea that an interviewee's answer to this question will affect the employer's hiring decision, and the law says it should not.
This is fitting into the same category of not being able to ask candidates; what's your sexual preference? what's your religion? do you smoke? are you planning on having children? etc. as part of the hiring process. They are rules that help avoid discriminatory hiring practices. At the end of the day they help companies more than the individual. The individuals are already protected from discrimination and could sue if these questions came up during an interview and they didn't get the job. Banning these questions ensures companies and their interviewers avoid situations where they could become legally liable.
Whether salary info helps the company or individual more is debatable since this does not represent a protected class, but obviously the goal is to support the individual.
I happen to think that all workers should have protections, not just those in unions.