Alright, let's start with the first fact, which is that a lot of companies do not have tax liabilities because they are using net operating losses, which is perfectly reasonable and has been a bedrock principal of corporate taxation since time immemorial.
Second, the fact that companies (and individuals) can offshore their tax domiciles is a check against tyranny from my perspective. There is a point when taxation becomes confiscatory, and offshore tax domains force the US to actually be competitive about taxation. It prevents the Federal government from arbitrarily taking constantly. And frankly, there's nothing you can do about it. What are you going to do, make companies that are domiciled elsewhere illegal? Good luck with that.
Plus, they're essentially doing to the US what multinationals have done to other nations for decades - repatriating earnings elsewhere. The problem you all have with it now is that instead of repatriating to the US, they're repatriating to the Grand Caymans. Well, if you don't like it, you should be a more competitive domicile. The dialogue is one of rational benefits, and transfers of value; drop the victimhood.
This should be a wakeup call to those who constantly advocate treating productive entities and people as though they're piggybanks from which politicians can draw constantly to feed their pet projects. Increasingly we live in a world where private actors don't have to tolerate that sort of thing, and therefore governments must reasonably charge for the services they provide, or face a loss of revenue. As individuals become more mobile, and as technology allows greater and greater telepresence, this will become a major factor in taxation. It's competition, and it's about time governments face it.