Western bishops, led by Rome, repudiated the Henoticon because it ignored creedal advances made by the Council of Chalcedon regarding the relationship between Christ's Godhead and manhood. Emperor Justin made Theodoric more suspicious, furious even, by depriving Arians of their churches in the eastern half of the empire. Theodoric remonstrated with Justin. To pretend to dominion over the conscience is to usurp the prerogative of God. Justin thought not.
Society requires unity of belief.
Theodoric ordered John to travel to Constantinople and convince the emperor to restore the churches. He was committed to stamping out heresy, not pleading for it. Theodoric hinted darkly that he might go to war against Justin in behalf of his beleaguered co-religionists. Reluctantly John began the wearisome, dangerous voyage to Constantinople. Along the route John was hailed with joy by great crowds.