The question is: why is the US entitled to these taxes, such that avoiding them becomes unethical?
False equivalence. You can deduce anything that's used to generate the profit. This makes sense.
> The question is: why is the US entitled to these taxes, such that avoiding them becomes unethical?
The answer to this question is the same as the answer to the question "why is the US entitled to taxes".
Pretty sure you wouldn't consider that one one that makes sense.
Plenty of deductions exist for a reason, and generating profits isn't always one of them.
Various reasons: 1) to segregate assets, 2) because certain regulators will apply restrictions on certain security actions (one example: it seems the Belgian regulator has barred investors from borrowing against their stock holdings for most purposes, but this is possible with a US broker, even for Belgians, without restriction), 3) to stop double taxation which would be bad for global investment (e.g. some pension funds are tax exempt under local law), and 4) because investor A living in country B doesn't want to pay taxes in country C, he wants to pay taxes in country B under the laws he knows and understands.
Imagine living in Greece, and then having to figure out the entire tax system of Spain. In a foreign language. It would probably be too complex to bother (and thus you wouldn't invest) or it would be an expensive undertaking (lawyers etc) eating into your returns.
Investing in a CaymanCo is generally easy -- you don't pay tax at the entity level, you pay tax in your personal entity. Clean, easy, and you can ride off on your boat into the sunset.
I think you are confusing the fund with the mangement company.
An asset manager is a company that manages assets for investors and charges fees. They have employees and offices and profits and pay taxes. Fidelity's parent for example is a US based LLC.
An asset manger like this runs many funds on behalf of investors. For each investment fund, they setup a fund to legally ring fence the assets for that particular fund, which they manage on behalf of the fund's investors. This protects the investors and maintains separations of the assets. If the management company went bankrupt, the funds themselves are unaffected (aside from needing a new manager).
The fund itself has no employees, it's just a method of legally separating out those assets.
I would also point out that this particular case has nothing to do with the US. The manager in question is not a US citizen or resident and I would be extremely surprised if the management company was being setup there.