[PugetSoundSoldier]

No, I mean where is your documentation of a requirement of celibacy for married men who come to the Catholic Church as priests of other churches.

See the Holy Orders that I referenced above, given any time a priest is welcomed to the Church:

You will be required to continue in the service of God, and with His assistance to observe chastity and to be bound for ever in the ministrations of the Altar, to serve who is to reign.

The words are direct and unequivocal. Regardless of his status as married or not. The candidate is required to observe chastity.

Furthermore, celibacy is and remains a voluntary vow.

Apparently your understanding is different from the oath taken by priests during ordination. They are required to observe chastity.

[Petronski]

Those welcomed to the Catholic priesthood from other churches are NOT required to remain celibate within their marriages.

You are arguing from the general with a presumption it applies in the specific. You need to prove the specific. Even the Catechism paragraph you cite acknowledges this:

1579 All the ordained ministers of the Latin Church, with the exception of permanent deacons, are normally chosen from among men of faith who live a celibate life and who intend to remain celibate "for the sake of the kingdom of heaven."70...

Apparently your understanding is different from the oath taken by priests during ordination. They are required to observe chastity.

The vow is voluntary because becoming a priest is voluntary.