Requesting clear evidence that sex (with age difference) is harmful to minors.

If such evidence exists, at which age is the cut-off? Why is the cut-off age (age of consent) different in different countries?

If such evidence doesn't exist, why do professionals still insist upon believing it as if it was the absolute truth, and justify extreme measures against anyone who counters them, wants to have sex with minors, or does have sex with minors?

Is there any logic to this topic, or is it all just double-standards, hypocrisy, pretense, and irrational?

I would also ask whether pedophilia is a disease, but current scientific consensus seems to say that it's just a sexual orientation.