Religion has nothing to do with homosexual people. We're talking about freedom, and in these case freedom means everybody can fall in love with whom he/she likes. Then, if two men or women want to get married (they don't need to, but that's the same for heterosexual couple) why can't they not??
"To have and to hold, from this day forward, for better, for worse, for
richer, for poorer, in sickness or in health, to love and to cherish
'till death do us part."
Two men (or two women) can do this the same. But if the Church doesn't approve the homosexual marriage, then they can get married in the registry office (in some countries, like Spain e.g).
The most important thing is that we learn not to interfere in the other's lifes. You are heterosexual? Ok. But be tolerant and accept there are people who love in a different way than you and must have the same rights.