If I remember correctly Boaz once mentioned that he makes 6 figures. Knowing the market and his job I can guess about where that puts him. He is in the income bracket that pays the highest percent of taxes when FICA is taken into account. So yeah you aren't going to get him to budge on a flat tax cause he is paying a metric crap ton of taxes right now.
That income bracket gets reamed in taxes and it's probably the 1%'s best allies in the battle to lower taxes, they look at their tax bill and about have a coronary every year. Then they see people getting section 8, food stamps, expanded unemployment etc. Yeah they are pissed and guess what they have every right to be they are the ones funding the government not the rich, not the poor that ugly spot just shy of upper-middle class.
Now that I have defended you Boaz one question for you. Should Bezos pay the same rate as me given that his wealth was built almost entirely due to existing infrastructure? Or perhaps should he pay a bit extra due to the fact that his wealth is dependent on putting massive wear and tear on the transportation infrastructure? Not even counting the money the government has poured into the internet infrastructure that he is also dependent on where as my wealth is mostly built using local and toll roads and could be earned regardless of the existence of the internet.