I don’t understand why there is so much emphasis on the actual “marriage”. Regardless of whether they are “married” or not they will still do their aveiros. The “marriage” isn’t a heicha timtzah to it. Why should it matter whether they are allowed to get “married” or not?
Just to be clear, I don’t endorse this aveirah chamurah. I just don’t understand why there is any emphasis on something that will not stop people from being oiver to begin with.