The point they are trying to make I think is that tits aren't porn, there is nothing inherently sexual about tits or nudity, and covering it up and acting like it is something forbidden only serves to increase the mental health and family issues you talk about. I think blood or a sliced eyeball are a bit different in that it's a deep-seated instinct to be averse to those things because they are signs of physical trauma.

For example, in societies where no one covers their breasts they aren't seen as sexual objects, something else like knees or whatever becomes the sought after sight. Though I agree with you that if someone wants to avoid something that might cause an unwanted reaction they should be able to do that, we obviously aren't at a point in society where no one has a reaction to sudden tits.