What is wrong with some transparency? What is the benefit of keeping that information under lock and key? Who benefits in particular? It seems like only the referees benefit. No one in the audience or even on the fields, courts, or rinks gets to have a final say on a referee's decision except a referee. Who cares if the referee is hated? As long as the person is fair and true to the rules, that's all the matters.
Visibility of performance is important, especially when it comes to a possibly high stakes job like being a referee. Just like any other job, they should be held accountable for their actions and they should be up for review by other people. This will also help them work to improve their calls, thereby improving the quality of the games.
Like any other job in America, referees have their problems, times when they are just flat wrong. But unlike the average American, the times the referees are wrong can cost a team a game, and gamblers (whether legal or illegal) tens to hundreds to thousands of dollars. It is very necessary for the people to see what referees are good and which are bad.
The problem with posting the performance of referees is that whether or not they are good or bad the spectators of said sport will already have a predisposed opinion of all calls during the match or game. With this basis to start off with not everyone will be able to respect the referees calls. When it comes down to it, the referee is trained to make these calls and viewers aren't until there is sufficient evidence that a referee is habitually wrong then perhaps his performance can be legitimately be questioned or posted.