Interaction of a lot of things.
1. It's xeno, but it's also familiar. We all know what cat hair feels like or the way a dog's tail expressed.
2. Lots of pop-culture points in our youth involving animals or anthros and romance thanks to cartoons and video games.
3. Well, come on, there's a bit of the old-fashioned bestiality in us all. It's part of our heritage. (see >>116237676
4. Tails are hot and fuck anyone who says otherwise.