That's a good point, Akir, except for a few things you may be overlooking. This is a Japanese product for japan-only. In Japan, porn is much more prevalent, kids are exposed to it in every magazine shop in the country, and it's often very hardcore stuff. It doesn't phase them, they're not as repressed as the kids in a lot of western countries.
That said, kids don't buy $300 PSPs. They steal them, or get their parents to do the buying. Thieves are already corrupted, and parents who don't police what their kids buy are a far, far more serious problem than kids watching porn.
I'm of the opinion that a kid who's old enough to be interested in porn is old enough to handle watching two other people have sex, and kids who aren't yet physically mature enough to get turned on by it won't understand what they're seeing, and will watch something else.
Americans, and no doubt other countries, try to repress their desires. Physically most of us are ready, able and willing (if not eager) to start fucking like mink by the time we're twelve to fourteen years old. In "the old days" girls used to be considered spinsters if they weren't married and popping out children by the ripe old age of sixteen. That our modern social beliefs, misguided as they may or not be, dictate that kids need to be protected doesn't mean that, in fact, they really do.
Kids are smart, parents are slacking, and Sony sucks for many more reasons than this. =)