because they are part of a stupid religion. sorry, but that's my view.

Hopefully this bit of information will explain it more fully than what I can say off-handed; Due to the widespread illiteracy of the scriptures, especially that of the Gentile believers who were totally ignorant of the Torah, whatever the Catholic priests said were considered as God’s Law and divine truths. One area of total distortion was that of marital relationship. Surprising to almost all of us, it was common for Catholic priests to have multiple wives and mistresses. In 726AD, it was acceptable for a man with a sick wife to take a second wife so long as he looked after the first one. With concerns for protecting Church property from inheritance however, offspring could not inherit church property and it was later declared that all sons of priests were illegitimate. In 1022, Pope Benedict VIII banned marriages for priests (monogamous or polygamous). Finally in 1139, Pope Innocent II voided all marriages of priests and all new priests had to divorce their wives. All these were done to possess and protect money and church property. Making polygamy a sin and marriage unacceptable for a priest was a slow and purposeful process. If you wish to read the whole account here is the source: http://www.patriarchywebsite.com/monogamy/mono-history.htm

Simply because of the man made traditions of the Catholic Church. Celibacy for priests is not required in God’s Word, the Bible. The New Catholic Encyclopedia concedes that “the law of celibacy is of ecclesiastical origin” and that “ministers of the N[ew] T[estament] were not obliged to celibacy.” Many of Christ’s 12 apostles, the foundation members of the Christian congregation, were married men. (Matthew 8:14, 15; Ephesians 2:20) Paul wrote: “We have authority to lead about a sister as a wife, even as the rest of the apostles and the Lord’s brothers and Cephas [Peter], do we not?” (1 Corinthians 9:5) Writes Peter de Rosa in his book Vicars of Christ, “[priestly celibacy] has probably done more harm to morals than any other institution in the West, including prostitution. . . . [It] has been more often than not a stain on the name of Christianity. . . . Enforced celibacy has always led to hypocrisy in the ranks of the clergy. . . . A priest can fall a thousand times but he is forbidden by canon law to marry once.”

It started as a means for the Catholic Church to protect their property. Their assets are first and foremost.

Because Roman Catholic priests don't like women. They're only into altar boys