Can someone please tell me a reason why people shouldnt be able to chose who they want to marry?
Well, the thing you have to understand is that marriage is not an inherent right. It isn't something that government must
allow people to do, because marriage itself-- in the sense of legally-recognized marriage-- is an agreement with the State that comes with specific legal benefits. It isn't "a church thing", because churches are allowed to sanction marriages however they see fit; many churches do, in fact, perform marriage ceremonies for same-sex couples.
It is within the State's prerogatives to decide under what conditions that legal recognition and those legal benefits may be granted. The State's refusal to recognize marriage between same-sex couples does not prevent them from being married by their church or from living as a married couple.
As for why same-sex marriage might not be allowed, there are specific reasons why legally-recognized marriage receives the benefits it does. Those reasons pertain mostly to resolving inheritance and custodial disputes in court, which is primarily a concern for couples with children. Since same-sex couples-- unlike the vast majority of opposite-sex couples-- do not naturally produce children, providing them with the benefits of legal marriage is not necessary.
Of course, same-sex couples deciding to raise children despite this disadvantage are part of my argument
in favor of recognizing their marriages...
Why do we still debate this I think its pretty clear that if people cant chose who they want to marry then doesnt that mean that not everyone is born equal?
There are a lot of restrictions on legal marriage. We're not allowed to marry close blood relatives, for instance, or more than one person at a time. Every single State has a minimum age requirement for marriage, and in most States it
isn't the same as the age of consent. Marriage to foreigners is tightly regulated. And several States have other requirements which must be met by prospective newlyweds before they can be legally married, ranging from marriage counseling to blood tests.
Do these restrictions mean that people who conflict with them are "less equal" than people who have no problem with them? Or does it simply mean that the State has certain requirements for a relationship to be recognized as a marriage?