It’s strictly a personnel issue. God himself said that celibacy is desirable. The church listens to that counsel. There is no sin in marriage, nor has the church ever said that there was. But if the church uses the Word of God to discern whom the most qualified to be priests are, who are you to criticize them for it?
And, for the record, the Church does address the issue of priestly marriage as an issue of personnel, not as morality. Priests who are released from their vocations before seeking out a wife are not condemned; priests who were married outside the discipline of the Roman Patriarch (which is a seperate office from the Pope, although occupied by the same person) are recognized as holy men. The moral issue arises only when a priest has taken a solemn vow to remain celibate and to obey his patriarch, and then breaks that vow.
Criticism seems warranted when, during a time of dire need for filling offices, otherwise entirely qualified men are rejected for the single offense of having a wife.