Uncle Tom has a different meaning. There are terms like Oreos, or coconut that imply a black person is black on the outside, but white on the inside, as in, they act white, but appear black. I can see how that could be perceived as racist.

Uncle Tom has a specific meaning a black person being overly deferential to, or appeasing white people, as a sellout to their own race. It comes from an old character in a book of a “virtuous” slave. It can also be used for any minority person complicit in their own groups oppression.