If a religious bigot wants to discriminate against gay people, well, that's not great but up to them. When the state wants to discriminate against gay people that's worse, especially since "right to a family life" is a human right.

Well, no. I guess not. And in that context, there will definitely always be a broad spectrum of those that want to keep traditions as such, and those that want change.

But it seems that at least for this particular tradition, it gets trickier to just consider it "a tradition" since it is so intertwined with the legal definition, for some countries at least.

So even though it's "just" a cultural tradition, it makes a big effect on the outcome of legal matters.

I mean, I've seen groups that oppose same-sex marriage suggest calling that "legal relationship between two people" something other than marriage, giving it the same rights and that would be enough.

The thing I try to imagine is, what would happen if some country would completely decouple the marriage term from the legal definition, if that would make things better or not.

As long as every legal matter related to the definition of this new term is updated, and so referring to marriage would only be at the religious level (no other consequences than that), what would happen? would that be a good solution for most? or would it be maybe just enough ?

I'm pretty sure there would be people disliking the idea of having a different term, however legally equivalent it may be, and probably they could give good reasons, but would it be the majority or a minority?

I have honestly no idea.

You can't exactly do it from first principles, or from Euclid's five axioms. It's arbitrary, but it's an arbitrary part of the society we live in, so there are reasons why marrying - as opposed to just 'pairing up' - is optimal.

1. Family rights - if your partner is sick and in the hospital, marriage allows you to make decisions on their behalf, gives you visitation rights, and allows you to receive benefits if worse comes to worst. It also gives you greater rights when it comes to any children you may have.

2. Taxes - the government gives incentives to married couples. (We could argue that in states where gay marriage is prohibited this is not the case, but that just sounds like more discrimination.)

Noone is forcing religious organizations to perform gay marriage ceremonies in their places of worship.