Discrimination laws are based on genetics and religious beliefs. Homosexuality is neither genetic nor a religious belief. What you are demanding is that society redifine society so you can feel good about relationships that really don't need a piece of paper to feel good about.
Like I posed, if you don't like the situation get out and work to educate people and change the laws. Complaining about religious beliefs is not going to make those with religious beliefs change their minds. If anything the tactics being used by those seeking to legalize gay unions will only garner enough support from the electorate to pass a Consititutional Amendement limiting marriage to one man and one woman. What issue do you think really put Bush in the White House for a 2nd term?
As to the why, it is called conviction.
As to what I refered to as petty debating tactics is your use of the phrase ab hominem, which is an overused phrase by those who cannot address an issue. I have not posted an ab hominem. Do you know what the phrase means?