That's not to say pedophilia was justifiable in the past when people were expected to act like adults earlier, of course.
Research and tradition have said we naturally "come of age" around 16 to 18 (I think 18 is the safer bet now).
Like others said, pedos like the
Muncie Molester are so terrible with women their own age that they try to take advantage of very young people who don't know any better to get laid.
That's why "half your age plus 7" is a good "rule of thumb" for relationships, even if a relationship is otherwise legal.