So at 15 you're still a child and can be easily influenced but, a few months later, at 16 you're not? My point is that yes she was legally a child but only legally. Whether or not we can actually class her as a child who is too young to have sex is a different topic that cealry different countries differ about.
I understand his point but there's a difference between a lack of law and differences of law. The fact that there are differences regarding the legal age to have sex is enough to highlight that it isn't objective and that she was actually a child.
I've been 13, 14, 15 and I am a girl and I can tell you that we are inexperienced of life, boys, men, relationships, too trusting and easily manipulated. Adam Johnson had many more years experience and took advantage.
If you don't mind some 20 odd year old bloke coming to your house and trying to stick his nob in your 13/14 year old daughter then you have big problems and aren't mentally mature enough to see why it's fucking wrong.