How very Christ-like of them.
Yes, actually. The New Testament - and Christ - laid out the procedures for Church Discipline, which is what he is describing. What would have been
unChristlike of them would have been had they instead decided to prioritize worldly benefits over the deadliness of sin. Loving someone is not the same as enabling them.
Jesus actually stated that if someone was committing sin within the Church and refused to change after being confronted first by you and then by the body, that yes, in fact, you were to shun them. The Epistles repeated this direction, and mentions examples of it happening. Once in the Early Church (in the very first days) when a couple lied to the Church (and to the Holy Spirit) regarding money, the penalty was 