Incest is bad, having experienced (unnecessary elaboration here) firsthand.

I just find arguments about genetics uncompelling. It’s an added risk factor, absolutely, but nowhere near what I consider the most dangerous aspect of incestuous relationships.

It is, however correct a line it may very well be, also borderlining on eugenics adjacent arguments I think. It is not necessarily a slippery slope or anything, but when discussions about who should be allowed to reproduce occur, it should be expected that people would get a little prickly I think, even if it’s a justified idea.