> we're talking about all Black people, Indigenous people and women

Yes. Athens was similar–a minority of the population could vote. It was a deeply flawed democracy, but a democracy nonetheless.

> That some of the colonizers can vote isn't really relevant

Literally America! Also all of Europe depending on when you draw the line. Also all of the Middle East for the same reason. (Also most extant Native American tribes.) Hell, even in Palestine we can only say more than 50% of the population traces from Bronze-Age heritage.

By your definition, democracy does not exist and cannot exist in most parts of the world.

> this can help us reflect on the true nature of the US

It really can't if we're redefining precedented terms. America, like Israel, is a flawed democracy.