Totally agree, but I don’t think we are talking about the same thing here. What I think you are talking about is discussing salary history as part of negotiations which I agree with, but what I’m talking about is employers requesting salary history right up front and using it as a go no go towards an interview.
It is a red flag to me when this question is part of the initial screening process, whether it is on an application or from an HR screener or an up-front interview question from a hiring manager, especially when it’s made clear that it is “required”. Granted it will screen out applicants that you might otherwise waste your time with, but on the other hand it may screen great talent out of an interview that could lead to mutually beneficial negotiations.