You implied that the poor whites never had power over anyone at any point, which is patently absurd. And, it's not just lynching where they exerted power. They could beat black people without impunity and did, rape their women, tell them to get the **** off the sidewalk, call them boy, steal their land, kill their livestock, etc., etc. and face zero repercussions Clearly, none of this shit is allowed or practiced today, but to suggest that, at any point, 99.9% poor whites didn't exert any power to match their prejudices is utterly idiotic and factually wrong. Power was asserted daily, in big ways and small. So, getting back to the original statement, yes, it's likely the result of this constant exertion of racism that the perception of racist still remains, even if it doesn't necessarily fit.
But, by your definition, poor white folks would seem to not be capable of being racists today because they would lack "power." I agree with everything you said about the past that poor whites did have power over blacks, but that's not true today.
I like this definition of your definition - "Prejudice plus power" is a (re)definition of "racism" used by various ivory tower types and social justice... enthusiasts to prevent accusations of racism (justified or not) against not-so-powerful groups (i.e. non-whites). While the usual definition of "racism" is something like "prejudice, discrimination, or antagonism directed against someone of a different race", some academics reject this definition and require an additional condition of "...by someone in a position of power over them", thus rendering those without "institutionalized power" incapable of being racist. Obviously, the majority of racism in the US is against minorities by whites, but this definition makes the converse categorically impossible, rather than just less frequent.
That's not a bad thing, necessarily. They can still be prejudiced, even if they have no power. I realize that my definition is a fairly nuanced term, almost semantics, but I think it works pretty well even as the dynamics of race changes in this country.
So, then, you would agree that blacks are capable of being bigots or prejudiced, but not racists, and the same would then be true for the vast majority of all whites as well in today's society, correct?
Depends on what threshold one sets for the word "power." An example of a racist act by a black person was the very subject of this thread. It doesn't take life or death authority to have "power." Forcing folks to the back of the bus is a "power."