Of all the legitimate arguments to use against government union abuses, dumb arguments like this one undermine the good ones. The most relevant factor in compensation is the occupation. Lawyers, accountants, and engineers make more than janitors and dishwashers. If you're going to compare compensation between public sector and private sector workers, you have to compare occupation to occupation. Telling me that a government scientist makes more than an Enquirer delivery boy doesn't tell me anything useful.
We follow the "living room" rule. Exhibit the same courtesy you would show guests in your home.