I can't admit I understand exactly what's going on in this case, but usually the story is that companies claim they have no US tax liability on revenue kept in a non-US subsidiary.

And the same companies stuff all the non-US revenue into a low-tax subsidiary, even when it's effectively earned in high-tax ex-US jurisdictions to avoid their taxes too.

> I can't admit I understand exactly what's going on in this case

That's exactly the problem! These are extremely complex situations where there usually doesn't exist any clear answer. If there did, large corporations almost certainly would not take these steps.

If there were clear laws, then taking these steps could be criminal tax fraud. Blame the regulators.

There's nothing stopping nations from writing clearer tax laws.