Didn't JK say that her book touched on this topic ?
"On one level, my interest in this issue has been professional, because I’m writing a crime series, set in the present day, and my fictional female detective is of an age to be interested in, and affected by, these issues herself"
I'm pretty sure she meant she was trying to learn about today's gender ideology so she could write about a 20s-30s woman who has grown up immersed in this environment.
Not researching how a 1970s serial killer might use a disguise.
-k