I think Peanut was a symbol for his owner's and fans' masculinity. When the critter was confiscated and euthanized, his fans felt emasculated. This played into their fears that the progressive mindset emasculates them. And there you have it.

I remember a while back a kid in 4H made a pet of the goat she was raising as a farming project. When the goat won a prize and was sold, the child refused to release the goat. Eventually the sheriff came and confiscated the goat, who was killed. Comments I heard from the Right were along the lines of, sorry but the kid needs to learn what farming is about and where food comes form.