Rich people are surprisingly whiny about having to pay tax like the little people.
Disagree. You're appealing to envy.
In my experience, they'd be quite content to pay tax "like the little people". But they don't - they pay at a far higher rate.
It's the government and its rapidly escalating and unequal progressive tax rates that lie behind their gripes. When I last looked the wealthiest 5% in SA pay well over 50% of the personal income taxes, at a far higher tax rate than what you condescendingly call "the little people". Besides, a surprisingly large number of HNWIs in SA started off poor and disadvantaged, and built up their wealth through entrepreneurial effort and dint of hard work.