Here's a terrible analogy: I know I'm missing something, but at the same time it's not worth it to me. Soda tastes good, but I know all that sugar isn't good for me.
I think it comes from how sexualized furries and anime characters (why are they always childlike females?) are in modern culture, and that bothers me somewhat when I'm surreptitiously made part of that. It garners the same reaction as when someone is walking through public whilst practicing their kink overtly.
I respect the hell out of your right to do what makes you full, but you also got to respect my right to not want to take part. I don't feel disrespected, but I am in this moment expecting harsh judgement for that innate feeling of self preservation.
Don't get me wrong, I'd say the same if it were any other sexualized images, not just the ones on the fringes of what's considered 'common'.