See post 176 for why this doesn’t apply here. In a nutshell, Jesus was speaking to the clergy (in the form of the apostles) not the laity, unless its your position that each of us is able to “bind and loose”, i.e. validly administer the Sacrament of Reconciliation.
Similarly, the epistles that you cite were addressed tho the clergy leading local Churches, not to the laity.
So, then, your position is that we should not judge Hitler’s actions to be evil, because we should not judge. Likewise, we should allow a political envirement that will produce a second holocaust to happen, because we cannot judge and we cannot declare actions founded on Nazism to be evil and stand against those who promulgate Nazism?
Clearly, that’s not right, so clearly we can admonish when we see objective evil in action.
Also, 2 Thessalonians was clearly written to the entire church in Thessalonica. Paul addresses his “brothers.” That was everyone.
You are also objectively incorrect about the reference to Matthew 18. The context clearly shows that Jesus applied his teaching to everyone to bring it to the apostles.
11 "If your brother 12 sins (against you), go and tell him his fault between you and him alone. If he listens to you, you have won over your brother.
16
13 If he does not listen, take one or two others along with you, so that ‘every fact may be established on the testimony of two or three witnesses.’
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If he refuses to listen to them, tell the church. 14 If he refuses to listen even to the church, then treat him as you would a Gentile or a tax collector.
If he refused to listen, then tell the Church. The church leadership was the apostles, so clearly this teaching was meant to apply to everyone.
Furthermore, the entire context of Matthew 18 shows that Jesus switches back and forth between addressing the apostles and addressing everyone. The fact that the next few versus are addressed to the apostles themselves does not change the fact that the previous versus applied to everyone so that they could bring it to the apostles.
Also, the apostles were always united after the descent of the Holy Spirit, so obviously the only real disputes that would arise would be from everyone else.
Still further, you are very confused about reconciliation, bind and loose, and admonishment. Admonishment is simply to tell somone that what they are doing or saying is objectively wrong and to exhort them to repentance. Reconciliation is the actual forgiveness of sins. Bind and loose is the power to declare absolutely on matters of faith and morals. Clearly, only the magesterium and the Holy Father can do the latter; only a priest can do the second, but the first anyone can do. The proof is shown in the counter-example of tolerating Nazism for the same of remaining non-judgemental.
Still further, “admonishing the sinner” is one of the spiritual works of mercy.
Are only priests allowed to perform the spiritual works of mercy? Obviously no, everyone can engage in the spiritual works of mercy. (They are, by the way:
To admonish the sinner (correct those who need correction)
To instruct the ignorant (teach the ignorant)
To counsel the doubtful (give advice to those who need it)
To comfort the sorrowful (give comfort to those who suffer)
To bear wrongs patiently (be patient with others)
To forgive all injuries (to forgive others who hurt you.)
To pray for the living and the dead (to pray for everyone who needs our prayers) )