Yeah, US has a ratings system that isn't actually legally enforceable, as demonstrated by a recent US supreme court ruling. The US constitution enshrines freedom of speech arguably more powerfully than any other country.
In various EU countries, plus my own Australia, this is not the case. Australia is VERY picky about sexual references and pedophilia. This includes any sexual activity with someone who looks like they're a minor, even if they are a person who stopped aging at the age of 13 about 60 years ago or however old E-Sumi-Yan is.
And this game has a rating here equivalent to about 10-years-old and up.
tl;dr - there are international rating issues regarding kid portrayal that would need to be worked around.