Dont take the quote out of context, St. John Chrysostom was speaking as one without Legal authority to 'restrain sinners' with that said, even St. John Chrysostom excommunicated sinners, for that was within his authority; moreover, he is addressing the issue for a spiritual, not legal, perspective. The Oecumenical Patriarch is the Legal Authority over Mt. Athos, and shall I quote St. Paul's letter to the Romans?:
'For rulers are not a terror to good works, but to the evil. Wilt thou then not be afraid of the power? do that which is good, and thou shalt have praise of the same: For he is the minister of God to thee for good. But if thou do that which is evil, be afraid; for he beareth not the sword in vain: for he is the minister of God, a revenger to execute wrath upon him that doeth evil.'
Moreover, justionios, to take your argument to the logical conclusion, you would be arguing that a Christian state cannot punish murders, or even restrain them and prevent them from murdering again. His All-Holiness is the Legal authority over the Holy Mountain, and the monks (with an 'o,' not a 'u') are bound to him in obedience. And if they break communion with them, they loose his blessing to stay on Mt. Athos and must leave.