[Rule35]

Not equality of people, equality of paths. In an FPS the shotgun and the rocket launcher shouldn't be equal or there's no need for both.

imho the thing to do is take OPs suggestion, Paradox should make gay-marriage possible but have people refer to it in variable ways. Some egalitarian societies can call it marriage, others sodomy, etc. And then add other cross-cultural restrictions too, where civilizations may not recognize bi-religious or bi-racial marriages for various reasons.

In other words don't minimize the issue, lean into it in a CK way, deeply and unsettlingly.