Playing with percentages can get easily confused which is what I suspect happened to you because your math is way off.
Percentages are handy for comparison, but can be easily confused or used to conflate facts.
... a white man is several times more likely to be shot by a black man, than the other way around
Thus, 1/1,046,032 whites was an interracial murderer. A black person statistically has to meet over 1M whites to run into an interracial murderer (whitey is pretty safe these days, apparently).
You are simply reading the GPs text differently. It hinges on the meaning of the phrase "likely to be shot by a black man", where one can read that as either "likely, in the course of daily life, to be shot by a black man" (my interpretation) or "likely, upon seeing a young black man, to be shot by him" (your interpretation, and possibly the GPs).