Only an American could have written this answer. All other countries in the world use a non global taxation system.
Two basic scenarios:
1. US entity owns a company in the UK. UK company earns $100, pays 20% tax on that, and is left with $80. Declares a dividend to the US parent, and the US then taxes the difference (35% US tax rate - 20% UK tax rate = another 15% to pay). We're left with $65
2. UK entity owns a company in Sweden. Swedish company earns $100, pays 22% tax on that, and is left with $78. Declares a dividend to the UK parent, which is then left untaxed.
Why does 2 make more sense than 1? Because the money was generated in Sweden, and the fact that some parent/holding entity is UK based does not matter (like, at all).
Scenario 1 pushes US companies to expand abroad (i.e. through foreign M&A), and not repatriate any profits back to the US. It also makes it easier for non US entities to acquire US companies, because they can achieve larger tax synergies than a domestic US acquirer would.
A US company trying to achieve something like that would have to do an inversion, which sometimes can be hard to do.
The current state of the US tax code is a great example why Microsoft paid a whopping $2bn for something like Minecraft (Sweden based), or an even larger amount for Luxembourg based Skype. What can they do with that cash otherwise? It's not like they're going to repatriate (ever) without a tax holiday.