I don’t know the details of how holistic review “scores” applicants. I do know that most colleges want their student body to have a mix of family backgrounds, including some with college-educated parents and some with non-college-educated parents.
It seems very unlikely to me that a given level of parental education would automatically be counted at any fixed level, either positive or negative, as a “score” factor for applicants. AIUI, it’s precisely that kind of “algorithmic” quantitative scoring of applicants that holistic review is trying to get away from.
And, as I said, the point here is that nothing in this discussion so far refutes the report’s conclusion that standardized test scores are pretty much redundant as a measure of student achievement.