Under Hong Kong laws he can't be charged as an adult for things he did as a minor.

However, he wasn't a minor when he held elected office.

And it's no coincidence that the first set of protests went off when he ceased to be a minor and became a much more useful pawn for the US, after they built him up as some kind of messianic child prodigy in the preceding years.

And yeah, 18 is still just a kid in many ways, but so many of us fuck up at that age and spend our lives affected by the consequences. The difference between Wong and the people in this community who fucked up at 18, is that Wong will be able to get a book deal out of his fuckup when he gets out.