What is the benefit of insisting that the term "racism" only be applied in situations of power plus privilege? This hasn't been how most people have understood the term for many years (until recently).
Furthermore, at what level does power matter? China arguably has equal power to the U.S. on the world stage now. Does that mean that prejudice against Chinese people is no longer racism? Some communities in the U.S. are not majority white in any measure (population, wealth, whatever)...does that mean that there, it is possible to be racist against whites? What about students in a school who get picked on because of their race, where the majority race isn't white? If a family with strong bonds has parents who don't want their daughter to marry someone of a different race, the emotional bonds they have are perhaps the greatest power in the daughter's life...is this then racism? If someone is driving along in a big heavy car and chooses to run a stop sign in front of a pedestrian (while making prejudiical comments out the window), the person in the car at that moment has all the relevant power--so were they racist?
The with-power definition doesn't seem particularly easy to use. It seems almost arbitrary, like someone decided that a word that has very strong pejorative connotations because of referring to hateful individual actions was co-opted for national political / social use--an attempt to steal the power of the word from one context for exclusive use in a related context.
So, anyway, we could insist on this usage of the term "racism". But then we just go back to talking about "racial bigotry" and admit that racial bigotry can go in every direction...so what, really, was accomplished?