While the actions of the review-bombing author aren't cool, it's 100% bullsh*t to lay this at her feet. The problem is not one author leaving, what, six bad reviews on a book. It's a system where six bad ratings are considered an important sign of a book's quality.
In fact, I don't think it is... I think publishers are using this author as a scapegoat, rather than offering debut and BIPOC authors REAL support.
If publishers want to support authors of color, they should put their money where their mouth is. The should support their authors by marketing their books, mentoring them, championing their careers, etc.
The merit of a review should be based on its quality. A one-star "this book sucks," should not be considered useful feedback. If the author left thoughtful one-star reviews that point out issues with the books, then those may be useful for readers. (I think she is entitled to leave *a* review on a competitor's book, even if it's not a good look). The problem isn't that this author review bombed. It's that people consider "this sucks, 1-star," a worthy criticism.