There's no source because it's false. First, Americans do vote for more taxes on the rich, by-and-large. And second, those that vote against taxes for the rich are usually basing their votes on incomplete or otherwise factually wrong data.

Nearly all the people in the USA would be much more likely to become millionaires if overall taxes were higher for the rich. Less worrying about healthcare, more ability to take business and personal risks, more baseline tools to build ontop of (like roads, etc). Those that want reduced taxes on the rich would be directly harming their own ability to ever become rich in the first place.