That’s a completely different conversion.
And you might want to check Japanese conviction rates before making assumptions. Their system is damn near “guilty until proven innocent”.
Now, whether such crimes actually get reported, is again, another, different conversation. There absolutely are vile predators over there, as a judge publicly commented he thought it was weird he could get arrested for banging a 14-year-old.
But the ensuing scandal is also the reason why that dude is no longer a judge, and why the national minimum finally got raised.
Yeah, things aren’t clear-cut. There are several matters in which Japan is painfully behind, and being such a populus country you can find people with views across the board.
But a lax justice system isn’t one of them. In fact Japan almost certainly has a huge problem with ostracising and convicting the innocent. You might hear about people losing their jobs just for getting arrested, even if found innocent.
And while laws also definitely need improving, it’s happening.
The main problem with stuff like age of consent, is going to be communities and groups of people who are behind on these things, and thereby shielding individuals from justice by keeping the bad things happening out of earshot of society at large. Their justice system might be brutally ruthless, but that doesn’t help if it never finds out about the crime in the first place.