Why should companies disclose salaries?

I don't mean a band, which says something like $20,000 to 100,000, that's not a band. That's just throwing something in the air and expecting something to come out. I mean, a legitimate "We're looking for someone with this much experience, we'll probably pay them around this much." Because the people posting the jobs will turn around and argue, "Oh, we want to know how passionate you are. We want to know how skilled you are." Well, if you already know how skilled you want someone to be, you should also know how much you're willing to pay for them. So, yeah, sorry. That's something else that I'm quite passionate about.