You could argue many things are a "net benefit to society" but which are untenable for moral, political, or practical reasons. In this case, however, I think you have to exclude government employees to from society to consider this a "net benefit" instead of a zero-sum benefit. The benefit to society is offset pretty much exactly by the income government employees are screwed out of by being denied basic rights to negotiate for themselves (amazing that sentence can be written about a free country). It might even be net-negative if it turns out the government can't hire good people due to artificial wage suppression created by short-term thinking.