I'm not attacking anime as a whole. Just the disgusting pedo stuff that is being defended by OP.

There is a tremendous gulf between being attracted to a child or someone just entering puberty, who technically could produce offspring, and being attracted to someone who has completed puberty but isn't of legal age.

The first example describes a sick person that needs to be purged from the world.

The second is an example of someone that would be normal in any other time in history, but all things considered really should reevaluate themselves and why they aren't disgusted by being around someone that still acts like they're a child.