If I understand you correctly:
An employer denoting the salary of the job in question is constitutes a “demand that others obey”..?
That’s fairly instructive.
What might you think if an interviewee asked you for your sexual history..?
“Well, boss, I’m just trying to nail down if we have the proper chemistry, you see..?”
Or more realistically:
“Please give me the contact details of the past 3 people you have fired”
How would you like that...?
Why exactly do you need to know how much money they made at their last position..?
You’ve never created a single job for another human being, have you?
Which labor union are you a union thug with?
Salary history is a part of job history and I requested both for all prior employers. It told me about the growth of the candidate and the likelihood of finding a long-term employee. The salary was already determined before the job was posted.