[the_af]

It's true some people are very sensitive. This is the cultural/taboo part of the issue. From what I've been told, for some reason this taboo is especially strong in the US (correct me if I'm wrong).

In the end, regardless of the taboo, keeping salaries secret only helps employers. They are playing with a full deck of cards, while you -- the employee -- aren't. Not having access to this information is detrimental. For example, you do not know if you're being short-changed.

In your scenario, Joe's employer will have to explain why Josh deserves more money. The problem here is that employers prefer to avoid confrontation, and that sometimes there just isn't any reason beyond "because Josh asked for it and you didn't" or "because I like Josh more than you". This is why hidden information empowers employers but not you -- because you simply don't know when their decisions are justified or arbitrary. By making this information public, you make it more likely that your employers will be forced to provide non-bullshit justifications.