That's more a sign that US tax policy is not competing effectively for company domiciles than it is to say that the tax havens have it wrong. Clearly, they are banking substantial tax money (at substantially lower rates) at the expense of higher tax jurisdictions.
That's not at all clear to me.
It might be true that it would increase US government tax revenue, but
A. It's not clear that's true. There may be other reasons keeping businesses out of America (say, SarbOx for example).
B. It's not clear that increasing the revenue of the US government at the expense of the corporations (and their employees and their shareholders) is making us better off.
Re: B. You're absolutely right. I didn't think that all the way through to absolute effects. For me personally, it would certainly be negative, so I clearly blew it here. Upvoted.
I'm not seeing anything good in that.
The statement seems to make the common assumption that economics is a zero-sum game, that somehow the harm that other nations suffer makes us better off. But this is absolutely not true.
When anyone is better off, it improves the lot of all, at least marginally. For example, a rich USA is able to provide aid to much of the rest of the world; our ailing economy might make some people smile as they think that the richies are losing out, but that just impedes our ability to aid. Even indirectly, riches provide the opportunity to research better agricultural practices, better healthcare, etc., and those things wind up benefitting all. Any country that's richer can afford to be more environmentally conscious, and that's a boon to all earthlings.
So I'm not able to take any pleasure in the idea that other nations might abuse their wealth-makers as badly as we do our own.