So you agree these groups don't want more CS graduates, they want to take CS from men who want to do it and give it to women who don't.
That's not how this works. That's now any of this works. Generally speaking, college education programs are not a zero-sum game although it does get more like that as you get into the PhD research level where we tend to underfund basic research. Nobody is "taking it away" from anyone... they are just making sure women and girls perceive CS as a real option for them. That's not "sexism". It's "representation". I've worked in the software industry for decades. It's ALWAYS been a "sausage-fest" in every setting where you find coders: industry, academia, events, etc. Males are not hurting for access to CS programs, encouragement to take CS prerequisites, or to invest personal time in learning technology. Organizations that demand and protect the status quo are not called "advocacy groups" for good reason. Let me know when the rate of males going into CS drops precipitously to less than 1 in 5 and I'm happy to donate to your "Men's Rights Group".
AFAIK there is NO advocacy group for boys and men to become programmers.
The point is there doesn't need to be one at this point given that 82% of all CS graduates are ALREADY men and boys.
C++ is the best example of second-system effect since OS/360.