There is a process for deciding if criminal behavior happened, it's called a conviction. We've seen judges make mistakes assessing the reality of criminal behavior all the time in Civil Asset Forfeiture cases where the standard of conviction isn't required.

None of the confederates who asked their that disability be removed by vote argued that they didn't need to do so because they had not been so convicted.

Because those confederate involvement in the Confederacy was a matter of public record. If we had fought a war against a military force Trump had organized, and that force surrendered; then we wouldn't need a conviction.