The core of the issue is that he identifies with prince andrew more than anyone else because he personally is also attracted to 16 year olds. That's it. This line of argument has happened a handful of times before and it always ends with someone defending 40-16 abusive relationships to the absolute death.
The reason I find it so disgusting is that even as a 20+ year old, I had no interest in 16 year olds. By that point theyre just children to me. And anyone in my peer group who was in a relationship of that kind of age gap was either a creep or eventually went to jail. So to see someone actively defending something so more extreme than that makes my skin crawl. I can't even fathom a society where there is no taboo against that kind of thing.
Yeah your scenario can be true about Mad, but I would like to caution that it is not the only scenario. Mad might be the identifying with the 16 year old instead, and thinking to himself that: As he is a responsible, knowledgeable, and mature person, he would have known what to do in that situation, what to expect from the adults, what to expect from himself, and what would happen if he went along with them, and to extracate himself if things went badly.
Which is absolutely bonkers. None of that is even a remotely reasonable thing to expect from a 16 year old. At 16 to even early 20s, most people are still figuring out who they really are, where their extra-familial relationship boundaries are, much less what they want out of an adult relationship. I'm trying really hard to be charitable to him, but even I'm having difficulty believing he doesn't appreciate this.
Alternatively, maybe Mad is 16 or 18 years old, which would explain a lot of ****.