What does some people not filling out paperwork before moving to another country have to do with how the society treats 5-year-olds?

Please stop your strawmen. My arguments were to the comment on why Japan has a very low crime rate, not how and why it treats 5 year olds.

No. You were clearly insinuating that illegal immigrants are likely to commit crimes.

Maybe you didn't read the part about a conformist society and yet focused on the illegal immigration part due to your subjective inner bias because you haven't called anyone a racist online in the last 5 minutes.

I never said foreigners commit crimes, as if locals do not, but being very selective with your immigration does help keeping crime lower in every country that does so.

As a country you already have the crime rates of the locals, so you want to not import crime rates as well, therefore you want your immigration being a net positive across the board so you'll have to be very strict.

Why are people offended by an obvious fact?

Well, they aren’t?