There is a lot of data showing that salary differences for women and minorities are reduced in environments where there is more available information about everyone's salaries, to the point where I thought it was generally taken for granted. I absolutely believe that the poster was sincere in his intent.

If you haven't considered this before, here's an article that covers some of how it can help: https://www.bustle.com/p/sharing-salary-information-at-work-...