J-Dunc on church discipline

“You cannot deal judicially with a man for a logical blunder, though you may deem him intellectually weak or confused” (John M. Brentnall, Just A Talker: Sayings of John (‘Rabbi’) Duncan, p. 42).

Of course it depends how far off the orthodox path this “logical blunder” takes a person. Is the blunder a trangression in the doctrine of Christ (2 John 1:9)? Does the blunderer’s “confusion” contradict the apostle’s strong negation (cf. Romans 6:1-2)?