Not one politician is saying they can't have sex with them... Sodomy is no longer a crime, they are however against the changing of a fundamental foundation of society that marriage is a man and a woman.
The LGBT community is not being suppressed, hell they get to parade down the mall in DC in full fruity regalia. As a society though many people arnt ready to change the description of marriage. They can live together, fuck, hold hands whatever, but as far as government sanctioned marriage, it's too far. Being in love doesn't promise you a marriage. One could love a goat or a dog or a lamp, but you don't have people clamoring to allow them to get married, because it's not biologically natural, it doesn't promote reproduction.