I mean, what difference does it make to anybody?
I find Boris Johnson physically unattractive. I cannot conceive of a situation in which I would wish to have sex with him. But there are people out there who not only fancy him, but who have had sex with him. This does me no harm. It harms no other human being. Why would I take a moral stance on this?
If consenting adults wish to have sex, set up home together, whatever, what business is it of anyone else? I just don't get it.