Which is part of the problem - there is no biblical constraint on "teachers" being married - and the Apostle that recommended it added the caveat that this idea was his own and not something handed down by God...
The Church was a thousand years old before it definitively took a stand in favor of celibacy in the twelfth century at the Second Lateran Council held in 1139, when a rule was approved forbidding priests to marry. In 1563, the Council of Trent reaffirmed the tradition of celibacy.
Demanding all priests be celibate makes no sense...it is an unnatural state and also removes one of God's greatest gifts...marriage to a life partner where a man leaves his mother and father and cleaves unto his wife...and they become one flesh.
That's a very truncated view. See the Catholic Encyclopedia's discussion here, starting at the section headed "History of Clerical Celibacy".