No it's not. I just gave you non-spiritual examples (criminal and tort law) in which knowledge leads to increased accountability. Neither of those are "spiritual things."

In this sense it is, which is why I clarified. In this specific sense of knowledge=accountability, that accountability is spiritual.

That's not the premise I was challenging; I was challenging whether or not excommunication was a punishment intended to benefit the excommunicated.

My mistake. My premise is that it is not a punishment from the church, and I back it through the reasoning that the church operates under the jurisdiction that the Lord gave it, and that it was not given the authority to judge or punish. That is solely within the Lord's realm, as it is said many times in scripture. We also understand from scripture that the Lord loves us, above all else. From there, knowing that the church cannot punish and that the Lord set up the church, that means excommunication has to have a different purpose. This is where knowledge holding you accountable comes into play. In order to relieve one of that accountability, they would be excommunicated, so that they would not be punished harsher than they deserved in the spirit world.

This premise by its very nature operates with the understanding that the church does as the Lord wills. There is no way to prove or disprove this, because there is no direct or even indirect evidence supporting or denying this claim. It is based upon faith. So again, either OP believes in the church and what it says its doing, or he doesn't. Many people don't believe the church is doing the Lord's will, and that's perfectly fine, they're allowed to make that call.