I did not intend to neglect the presence of African DNA in White settlers whatever the source. I would certainly assume your premise that it came mostly from indentured servant unions. I would also agree that the Irish were sufficiently poor, culturally deprived, and loathed that a successful and self-educated black man would easily be considered by many an Irish women of the day to be a hypergamous marriage.
I didn’t write that matings between black men and white women were predominantly due to rape. What I wrote was that interracial rape did not end with emancipation and that today interracial rape is more black on white. If you will read my reply to Elle Bradley at https://medium.com/@glob_snark/to-elle-bradley-judging-from-your-ill-mannered-argument-anyone-can-guess-with-certainty-your-d524a315a20#.y2arbid5p you will see a reasoned understanding of the statistics cited at https://www.bjs.gov/content/pub/pdf/cvus0702.pdf page 30, table 42.
Most rapes of whites are committed by whites. All rapes of blacks appear to be committed by blacks. A small number of rapes of whites appear to be committed by blacks. A small number of the majority population suggests a higher rate than a zero percent of a minority population.
If you look at it as a mathematical question rather than as percentages, nearly 140,000 white women are raped by white men, slightly over 14,000 white women are raped by black men, and nearly 13,000 black women are raped by black men. Of course, the ratios don’t take into account the relative number of women of different races that individual rapists encounter. If the numbers were adjusted for that factor, the differences would not be as pronounced.