Pro-Pyongyang Protest March

Ticket? Just load them on a boat – head towards NK and when you hit international waters – give them the boot. Surely their dear leader has taught them how to walk on water.

You should read the excerpt more carefully.

“This didn’t sit well with the right wingers” which suggests that they took some sort of action against the pro-Pyongyang protest which then resulted in “police came(ing) out in force to avoid physical confrontation”

Right-wingers tend to make the distinction between “us” and “them” based on whether one is “inside” or “outside” of a group, usually ethnicity or nationality or religion. Left-wingers tend to make the distinction based on “above” or “below”, standing for the rights of those oppressed and exploited regardless of where they belong to.
In theory, left-wingers would be supporting the protesters putting the welfare of the kids before notions of allegiance and naturalization as you say. Right-wingers would be vehemently opposed to any actions that would benefit a group that refuses to give up allegiance to a hostile foreign entity at one’s own expense.

But shamelessly demanding support while refusing to give up one’s allegiance to a hostile nation … that flies right in the face of not just how right-wingers would view the world, but common sense in general.
Which would then be enough to make die-hard right wingers angry enough to want to attack the protesters, I guess.

“You want to live in another country as if you were still on the homeland?”

Why not? It works for the muslims.

I see your point, though I doubt most of those other ethnic/international schools openly advocate, as a matter of principle, the toppling of the socio-economical system which governs Japan (among most countries today). For all their failings, the Bolcheviks never approached the bourgeoisie for funding of their revolutionary activities; it just stinks of a lack of common sense.