Further to the issues of laws and amendments...
One thing that I find curious is the fact that homosexuality is deemed to be legal and not just decriminalised. The distinction I am making here is that it is completely legal to be a homosexual, as opposed to it being not illegal because the "offence" is so minor or un-police-able that it doesn't warrant a law in the first place. Another parallel I'll draw [loosely] is the distinction between "not guilty" and "acquitted". If you are acquitted of a crime, your pre-existing conviction is overturned but this is not the same thing as innocent, which only occurs if you're found to be not guilty.
So it's ok to be a gay person. Now, let's think about what the legal definition of gay is [note that in this context I'm using gay to mean both gay and lesbian, but I'm leaving out bisexual and trans-gendered for the moment]. Presumably, gay means a person who has a sexual relationship with someone of the same biological sex. Can we also assume that the person is consenting and of sound mind so we can eliminate issues of "state of mind"? I’m trying to be as precise as I can now.
Ok, legally speaking I'm leading to the point that being gay is not a psychological condition or state of mind, but characteristic in exactly the same way that build, height, or hair colour is? We are told that from a medical stand point, gay and straight are measurably different. Is this still true? In other words, being a gay person is [legally] not a choice, but living as a gay person is.
So my question is this. If it's legally ok to be gay, and it is a biological characteristic rather than a state of mind, how is it legally possible to discriminate against gay-marriage? Wouldn't this be the same as saying that marriage is only for people with four limbs or over 3.5 feet tall? Clearly there must be some legal protective measures to prevent discrimination in terms of a trait or characteristic.
I'm not sure if I have explained this thought process well or not, but I'd love to hear what you think. Does anyone understand the legal aspects of this?