Thats quite a straw man. There's a pretty big difference between using a benefit as intended and taking advantages of loopholes in tax law by creating multiple shell entities around the globe. You can argue they have a duty to shareholders to optimize profits, but let's not pretend it's the same thing as paying your taxes as the law intended.
As a US citizen you can't declare your income was earned in Ireland and avoid or reduce paying US federal income tax. You can't avoid US federal income tax even if you lived in Ireland and worked for an Irish company for that year.
You can't just renounce it. It's a quite expensive process. And naturally, once you have, you no longer receive any of the benefits of US citizenship. Whereas the companies in question get to avoid taxes while retaining the benefits of being located in the US.