PReciSioN
I think you're overthinking this,
PReciSioNI generally advise students to avoid getting "in the weeds" of a RC passage, because the GMAT isn't interested in our ability to quickly study and retain details of a subject matter that we're not familiar with (unlike the LSAT, which is interested in that - that's why I advise GMAT students to NOT use LSAT RC to prep for the GMAT - but that's a subject for another post).
If we just stay at the high level of the paragraph in question, we have:
Catherine Gallagher argues that
Blab engendered
Bloob because IDEOLOGY A provided a transition to IDEOLOGY B. She cites the example of CAVENDISH...
What would undermine Gallagher’s explanation of the link between Royalism and feminism?
Well, where was Gallagher's support to her argument?
She cites the example of CAVENDISH...
That's really all we need (and all we SHOULD need) to answer this GMAT question.