Ethnocentrism is the belief that your particular ethnic group is better than all others. Racism is the theory of a hierarchy of ethnic groups which was, in the western world, based upon the color of skin. I urge you to read Dinesh D’Souza’s book “The End of Racism” - thought provoking and a real eye opener about race and racism.
And note that I use “racism” with respect to the beliefs in the American Black culture because of the aspect of lighter-skin color being “better” than darker skin tones within the American Black culture. This indicates an embrace of the hierarchy of color, not simple ethnocentrism. Self-contradictory within a group which attacks the same beliefs if a “white” person were to express them; but there you have it.
Your definition of ‘racism’ is cold, precise, (no offense) pedantic, and probably correct, given the examples you cite. Nevertheless, we live in a culture where words carry more than their strict dictionary meaning. And so “gay”, implies happiness, “choice” implies freedom, and “social justice” implies goodness, and who could be against happiness, choice and goodness?!
And so, “racism”, a concept that had to be invented, and some say was invented by none other than Leon Trotsky, has come to be associated, subliminally or not, with none other than the evil monster Dr Mengele, and whether Trotsky was the one to invent it, the Soviet propaganda machinery throughout the world (via their media agents and useful idiots) used this idea to fight the West in the field of politics, starting with the colonial Africa, and culture. The seed planted by the Soviets, no one else but them, has grown into a monstrous, infectious plant in the West, so that now more of us in the US and Western Europe believe, and the word is ‘BELIEVE’, in the existence of ‘racism’ than in the past existence of Jesus, and while we’re at it, in the existence of the Beatles. Yes, I’m saying that, as absurd as that sounds, ‘racism’ is bigger than Jesus and the Beatles!