If it was "entirely pushed by management" then most employees would ignore it, especially those making several hundred thousand or millions a year. On the contrary, a lot of employees at all salary levels discuss their salary.

Management absolutely has an incentive to hide salary writ large so that is definitely part of it. But employees who earn more than their comparably-titled peers also have an incentive not to disclose their salary. If position X gets paid, at the median, $200k a year with a $20k SD, and you get paid $275k a year in position X, the only things that will happen by you publicly discussing your salary are: 1) you'll be called a liar; 2) your peers will get jealous; 3) the best peers who may have been content prior, will either negotiate a higher salary and leave less in next year's budget for you, or leave for other positions making more money, resulting in a brain drain from your team.

Salary discussion overall only benefits low and mediocre performers. High performing ICs have very little incentive to discuss it.

#3 is called "fairness." It's the part where the rest of your team -- especially the women, who, statistically, are almost certainly making less than the median -- realize what the median is and have the opportunity to demand that they are paid for their contributions. Yes, that might come at a cost to you personally, if you were making more than others on your team who were adding similar value. Would you rather scam more money from the system for doing the same work as your peers?