The point of discussion is whether there has been a drastic reduction in female participation in CS since the early 80s. This is a point that is commonly brought up, based on the graph of the gender _ratio_ of degrees conferred (which is dominated by bachelor's degrees).
As this ratio has dropped only because the absolute male numbers have increased, it is unfair to attribute that to a reduction in female participation.
I never said anything about equal gender balance, in fact, I strongly believe anyone who aims for a 50/50 gender ratio in STEM has embarked on a quest for a holy grail that can never be found, for the same reason social workers and nursing will never be 50/50 gender balanced. The only way to get close is to actively discriminate against the people most interested in it, and this is both stupid and immoral.
By the way, during those crucial 80s and 90s, computer tech was strongly associated with geeks and nerds, and the popular image was that of socially inept rejects. But now all that has been retconned as women being discriminated against, because the hard work of those nerds has turned it into a lucrative and prestiguous discipline. The idea that women weren't welcomed is preposterous, those men and the communities they built have always been infatuated with any woman who considered them worthy of respect, and a minority of women have always been part of it too.
Women weren't becoming less represented in CS over time, because they were never welcomed in graduate programs in the first place
http://blogs.nature.com/naturejobs/2017/05/08/gender-gap-in-...