For some people it's possible for them to live with a significant intake of chemicals into their bodies that the cops call 'illegal'. They cope OK. It may even make them better able to cope with life. But for a substantial minority it's unsustainable, and it causes them to mess up their lives completely; NOT because the drugs are illegal, but because the effect on them is damaging.

I remember watching an interview with the former 14 yo YF of a Catholic priest. As he described it, he was regularly 'raped' before and after the Sunday morning service; which he spent in the priest's bed, waiting for him to get back. Now there's no way a 14yo is going to be 'raped' in that situation physically: clearly he'd enjoyed the relationship at the time. However in retrospect it had become a big negative; how far this was social pressure and how far it was a true reaction from the boy is impossible to know. BUT IT DOESN'T MATTER. The reality is that for many boys something that was good at the time turns negative later.

And it's in that experience that the wisdom of age of consent laws lies. The argument is that whilst at the time the boy may value the sexual component of the relationship, a few years down the line it becomes something deeply negative. That this happens enough to suggest that boys (and girls) need to be protected against themselves is the basis for a Age of Consent law. Therefore the reason for a BL to resist his YF's seduction is that there is a substantial danger that his YF will regret it one day; if we truly love our YFs, then we need to recognise that it may hurt him a lot. And so we say 'no'.

All this of course ignores issues about what happens if the relationship is discovered and the boy is forced to testify against his AF, and shamed before most of his friends.

This, of course is before any attempt at a Christian argument, which sees sexual relationships as only positive within a permanent relationship. That the attraction of an AF and his YF will always be short term (at most years not decades) means that it is defective from a Christian perspective