It's not something that bothers me much, there's a fairly rigid scale that I'm on so even if you don't know precisely what someone is getting paid if you know what grade they are then you can narrow it down to within a few thousand pounds easily even without having payroll access.
If, however, someone is sharing confidential information relating to your employment then I can understand why it's an issue i.e. if there was a culture of secrecy around pay then I see why you'd be upset but it's not the same for me.