The definition of "racist" is so malleable that anyone wanting to slander another person with that accusation is basically free to do so.
It originally meant a person who hated or scorned or sought to harm people of a particular race. The definition has expanded to mean, Anyone who believes there are differences between the races. For example, if I say, "Black people are better sprinters than white people," that makes me a racist. If I say, "I refuse to consider race in any of my inter-personal activities," that makes me a racist. If I say, "All lives matter," that makes me a racist. If I say, "I am color-blind," that makes me a racist.
And of course, under the current cultural regime, only European-based "white" people can be racist. At least in this country.
If people call you a "racist," wear it with pride. Our current President has done more to help "people of color" than any Leftist in the country, but his being a "racist" is common, accepted knowledge. **** everyone who hurls that particular slander against Trump. They are ignorant ass-holes.