Inch by inch, the social justice warriors are getting closer to the truth that boys dominate these fields because of all of their informal experience. Why? Because boys tend to be more willing to go against peer pressure and do what interests them. Male nerds and geeks may resent peer pressure and bullying, but they'll stick to what they like. Never met a single boy who took the attitude that he couldn't pursue his hobbies because of peer pressure unless those hobbies were things you don't mention in polite society (and maybe even make the avante garde squeamish).
No, girls don't need "more pushing." It would be a problem if a family let the sons fire up an IDE, editor + interpreter, etc. and told the girls that that was forbidden for them. I can pretty much assure you, that in the vast majority of American households, even religious ones, that doesn't happen. What naturally happens is that the boys will say "this is cool" and try it out and the girl will make all sorts of excuses ranging from lack of interest, to what would her girlfriends think.
And no, boys by and large don't put pressure on girls to not share hobbies with them. I've never met a red-blooded male who thought a generally feminine female who shared most of his interests was a bad thing.
I don't think that your conclusions are entirely correct.
Boys accept being ostracized from the mainstream more readily than girls, and ostracized boys form their own culture. One of those cultures revolves around technology past the point of being a simple user of it. To a degree it's involuntary. There are girls in that culture too, but in my anecdotal experiences many of the girls are there more by choice than out of necessity.
The nature of manipulating technology lends itself to those that are accustomed to isolation and to spending very long periods of time working on something to the exclusion of other things. Those that find themselves alone already start out with a perverse advantage in that regard.
"Ninety percent of baseball is half mental." -- Yogi Berra