All of these organizations operated at their zeniths during different time periods, governments, cultural norms, and a variety of other factors. The problem with the conversation you're describing isn't moral relativism or that everyone in it has equally valid points, it's that none of them seem to be capable of isolating the elements of those organizations that functioned/dis-functioned without endorsing/criticizing the organization as a whole while still presenting a cogent argument.

We could save a lot of money and time by replacing the Supreme Court and Congress with one person each. Do you think there might be any disadvantages?