Um
I think if someone is making money in the UK then intentionally and knowingly squirreling it offshore to avoid paying UK tax on that UK income then many would judge that to be “evil” as you say.
Maybe your wifes family did just that historically, maybe not. You can’t be accountable for their actions. If I was to inherit such an estate and I felt this was “not on” then I would look into how I can contribute back to society in a meaningful way with the cash that would have been paid to the state.
If I had been a bit lazy with vetting my investments and subsequently found out they had done something I did not agree with my money, I would mitigate this by withdrawing my investment, reinvesting inline with my ethics and values.