Playing Devil's advocate,

> You can't put a dollar value on a lot of contributions towards society

You could still measure whether any contribution is being made at all and only give BI to those who are contributing. Which is essentially what existing subsidies for art & etc are for.

> It also seems to me that, due to our racist and sexist history, there is a massive wage inequality geared towards industries that are dominated by white males. Who is paying for whom here?

Under BI, members of minorities who overcame those handicaps will be paying more in taxes to support a whole bunch of white males, though.