How many of us here have a pension, an ISA or even life insurance investment? They all come with tax breaks to basic and higher rate taxpayers. Are they morally questionable? No.
When the super rich do what they can to avoid tax then it can seem wrong to the majority of the population but, and it is a big ‘but’ if they make no call on the financial support system funded by NI, taxes etc, maybe they aren’t so bad after all? Is it ‘wrong’ to work within the Law to enhance (or protect) your financial position? The answer has to be no.
The tax breaks they utilise are available to everyone, the vast majority of us just can’t afford them. The fact we haven’t got the cash to make use of the facility doesn’t make it wrong. To a degree, calling it ‘wrong’ is the politics of envy, just to a different degree than the OP.
I am not an apologist for the super rich but relating their actions to theft is of spurious value. If you steal, destroy other people’s possessions it is illegal, it is morally indefensible. Using the system to maximise your financial security (to whatever degree) isn’t illegal, it may be difficult for ordinary peeps to come to terms with the fact that we don’t have as much money as a banker, a footie ‘star’ or whatever but if we don’t, we don’t.
Should the system be changed to tighten up on the use of overseas banks etc? That is a different question altogether.