I want to put an end to this argument, since I’m seeing it frequently touted and pointed to and nodded at like a mantra. Phrase it however you want: “it’s natural”, “it’s a biological urge”, or the corollary, “it’s unnatural”, “not even animals do it”, etc. There are variations - but the essential theme is to line up a (moral) claim with something called “nature”.
Heh heh. Join the club, my friend.