The Church vs Gay Marriage

How many of you get called stupid, bigot, old school for standing with the correct definition of marriage?

Isn't it amazing that liberalism preaches about welcoming all people and all opinions, but yet they seem to hate our ideologies and beliefs...apparently all opinions and beliefs are welcome until someone else has opinions that stand against liberalist ideology.

Why does the Catholic Church stand against gay marriage?

1601 "The matrimonial covenant, by which a man and a woman establish between themselves a partnership of the whole of life, is by its nature ordered toward the good of the spouses and the procreation and education of offspring; this covenant between baptized persons has been raised by Christ the Lord to the dignity of a sacrament."

This is a question that resolves into the Christian theology. We, as Christians, follow the traditional view of marriage according to the New Covenant ideology. As with all theology from the New Testament, it has ties with the Old Testament.
Matrimony is a gift of God, as it is proclaimed in Genesis 1:28 "God blessed them and God said to them: Be fertile and multiply; fill the earth and subdue it. Have dominion over the fish of the sea, the birds of the air, and all the living things that crawl on the earth." Of course not everyone is able to have kids as some people might be infertile, but in Matrimony two flesh become one. This is through love and the blessing of God.

1604 "God who created man out of love also calls him to love the fundamental and innate vocation of every human being. For man is created in the image and likeness of God who is himself love. Since God created him man and woman, their mutual love becomes an image of the absolute and unfailing love with which God loves man. It is good, very good, in the Creator's eyes. And this love which God blesses is intended to be fruitful and to be realized in the common work of watching over creation: "And God blessed them, and God said to them: 'Be fruitful and multiply, and fill the earth and subdue it.'"

Marriage serves a higher calling, one that indeed comes from God, as it is stated in Matthew 19:10-12: "The disciples said to him, 'If that is how things are between husband and wife, it is advisable not to marry. 'But he replied, 'It is not everyone who can accept what I have said, but only those to whom it is granted. There are eunuchs born so from their mother's womb, there are eunuchs made so by human agency and there are eunuchs who have made themselves so for the sake of the kingdom of Heaven. Let anyone accept this who can.'" For Catholics marriage is a Holy vocation not just part of civil matters.

Everyone must fight temptations, and homosexual acts close the sexual act of the gift of life. The scriptures condemns homosexual acts as a serious sin:

1 Corinthians 6:9-10 "Do you not realise that people who do evil will never inherit the kingdom of God? Make no mistake—the sexually immoral, idolaters, adulterers, the self-indulgent, sodomites, thieves, misers, drunkards, slanderers and swindlers, none of these will inherit the kingdom of God."
1 Timothy 1:10 "for the promiscuous, homosexuals, kidnappers, for liars and for perjurers—and for everything else that is contrary to the sound teaching"
Romans 1:24-27 "That is why God abandoned them in their inmost cravings to filthy practices of dishonouring their own bodies-because they exchanged God's truth for a lie and have worshipped and served the creature instead of the Creator, who is blessed for ever. Amen. That is why God abandoned them to degrading passions: why their women have exchanged natural intercourse for unnatural practices; and the men, in a similar fashion, too, giving up normal relations with women, are consumed with passion for each other, men doing shameful things with men and receiving in themselves due reward for their perversion."

But isn't homosexual (acts) also a common part of Nature?

Yes, this is the truth there is evidence of other species having same sex relationship, the difference is that humans are rational animals (from the scientific point of View) the difference is that humans can change the course of history, and philosophy too. A good answer to this is: In nature, evidence exists that there are some species of animals that commonly have prostitution and kill their mate...this doesn't mean humans should allow this in society too, does it?

Can society redefine marriage?

No, God defined marriage; no one else has authority over God.
1605 Holy Scripture affirms that man and woman were created for one another: "It is not good that the man should be alone." The woman, "flesh of his flesh," his equal, his nearest in all things, is given to him by God as a "helpmate"; she thus represents God from whom comes our help. "Therefore a man leaves his father and his mother and cleaves to his wife, and they become one flesh." The Lord himself shows that this signifies an unbreakable union of their two lives by recalling what the plan of the Creator had been "in the beginning": "So they are no longer two, but one flesh."