The reason people are very hesitant about sharing their salary is because we have constructed a culture where it is taboo to share what you make. That we have these ideals about how terrible things could be if you knew what others were making in comparison to you.
Her manager talked to her saying "Don't you know what could happen?". Well management couldn't fire her for that, but could make her work life less then ideal. Possibly holding back bonuses out of spite? Worse job assignments?
The huge job salary scandal that Google was a part of kinda shows hows they can't be trusted to be honest about salaries and supportive of their workers.
You feeling ok with what you are getting paid is not what matters. What matters is getting fair market value for your worth. Many people make less then what they are worth because they either don't know how much they are worth, or are even too afraid to argue for what they feel they are worth. Companies exploit this and use salary negotiations as a way to hire employees for the absolute least amount possible.
We applaud companies for making record breaking profits, but we don’t applaud them for decreasing their profits a bit in favor of increasing all their employees spending power.