TL;DR (most of it)
You'd be better off cutting these up into smaller posts perhaps?
Most people who are against what you're promoting are not, obviously, complaining about a 17yo and an 18yo having consensual sex. Hell, I had sex with my first girl friend when we were both under 16, and according to the law where we were and at the time we "raped" each other. Laws like those are indeed absurd.
Most people I know are not arguing against those things. What I am arguing against is when a 14yo ends up having consensual sex with a 25yo. What is my problem with that specific scenario? It's very simple, and you failed to ever mention it (unless I skimmed poorly which is a possibility).
My problem is that the older person in that situation is automatically a predator regardless of what the government's current laws state. Why? The older person is in a position of authority over the younger person. The same principle applies to work place and other sexual harassment offenses.
When you have power over someone like a priest does over their worshipers or a boss does over their employees or an adult does over a child, the relationship cannot be said to be fully consensual. They are not equals. It is very easy for the older person to manipulate the younger.
I'd love to hear your opinion on that issue. Also, please tell me how young you think sex would be okay regardless of the age of the older person. Is it 13? When they first bleed? Do you have any line at all, or is it simply up to the 9 year old to say they consent?
RE: Refuting Age of Consent Arguments + More *Revised Edition*