It's not really about confiscation.
In my mind, it's about getting what is rightly owed. The 0.1% (the primary target of these) are notoriously smart about hiding money from the tax man. Off shore shelters, real estate, etc are all avenues these people have that Average Joe does not. Many of these are objectively illegal, but they can afford a long winded legal battle that again your average tax payer just cannot. If we expect the true libertarian ideal of equal opportunity, we need to equalize the playing field in one thing everyone hates - taxes.
As a result, we need somewhat extraordinary measures to get tax money back from these people. They prospered using systems put in place by tax paying citizens (roads, airspace, internet lines, medical services, etc), and they should pay their fair share. It's not about being robinhood, to me it's simply about getting what is owed for the services they received (a more inflammatory argument can be made that Bezos and the Waltons in particular profit by leveraging social services to cover the delta between what they pay their warehouse workers, and what a working wage actually would be).
Any decent government should be able to enforce the laws it makes, including its own tax laws and its own employee protection laws. People who break these should face the legal penalty. People who don't break these laws should not be penalised under new made-up laws that are just easier to enforce.