Judgment is based on criteria. It does not stand alone as you appear to have it standing. Enumerate the criteria, and the reasons.
English law pretty much echoed the practice of the biblical era until perhaps a couple of centuries ago. The idea was to target puberty, the point at which the individual involved could understand sex.
Why take away the power of parents to grant the hand of, say, a 16 year old daughter to some other parents’ 16 year old son, when he is set up to be able to support her? I could as easily ask that.
You failed to answer the question I posed. Would you allow a six month old girl to have sexual intercourse with an 18 year old man? You are confusing a number of issues such as the role of the State or society and their relations with the individual, the definitions of homosexuality, pedophilia, the role of sex individually and socially etc. etc. It is judgement which is based upon common observation that physical and psychological harm befalls children when prematurely exposed to sexual behavior that results in laws governing sexual behavior.