I don’t think its about medical benefits.
I think its about tearing down society
You see it all the time, not just with that bunch.
The entire concept of "equality" to a liberal is not one of bringing the low up, but tearing down those who have excelled/succeeded and reducing everyone and everything to the lowest common denominator.
For those who worship their groin, regardless of orientation, this is about feeling better about themselves, sure.
But the economic benefits of the medical insurance provided to 'spouses' in situations where the applicants are very high risk because of their sexual behaviour cannot be ignored. Promiscuity among any group spreads disease, and in that particular group especially so due to the innate nature of their activities involving pathogen sources which most 'straight' couples would not normally encounter.