To be honest, it's reasonably ingenious and a rather old design.

Soy is strong and you need to be delicate with the dose.

recently they have screw caps and strange restrictors which let the sauce out and air in, but this predates that design. And the ones with a screw cap don't do retention.

If they put the air hole on the top, people will try to pour through it and make a mess.

if they put the air hole on the side it'd spill out if they didn't notice.

as far as i can thing, the only reasonble foolproof designs would be to retain the screw top lid german-style, and use one of the restrictor inserts.

But the two-spout cap, that's cheap and easy