It's a big ole pile of
petitio principii from what I can tell - the reason women didn't
continue to enter and prosper in the field of computing (as the narrative goes) is because the field was dominated by men:
>"Because if you're in a culture that is so infused with this belief that men are just better at this and they fit in better, a lot can shake your confidence." (Margolis, ibid) //
Hang on though, the main premise of the piece was that women were most dominant in the field and excelled [beyond the men?].
From personal experience I don't buy the narrative of computers being chosen to be "boys toys" as a move to exclude women, instead it strikes me boys chose computers, instead say of other things - like a social life. But that's maybe because the [apparent] anecdata they have contradicts my own experience, that my mother bought our computer, that it was in a common room and that my sister completely ignored it. At primary school (UK, 1980s) all the kids were given equal time on the BBC microcomputer during lessons, but it was primarily the boys who chose to stay in at break times and after school to use it. At high-school I was inspired by our IT teacher [female] as were others but AFAIR 90% of those staying to use the computers outside directed lessons were still boys.
That link actual goes as far as promoting the idea that boys were given computers and girls were physically restrained from accessing them [based on an anecdote]; to me that sounds like a misconstrual of the situation where boys asked for computers as gifts and so had them in their bedrooms - I can only assume that happened for some girls too.
If I'm wrong then nonetheless I don't think you can argue any similar narrative now, for the Western working and middle classes at least - if you have access to a smart-phone or a school/library computer you have all you need to excel at computer science; that surely eliminates any element of exclusion by sex from the field.
[+] In this connected digital world where no-one knows online if you're even human [woof!] the premise of male suppression in the proposed narrative would be defeated and a massive up-tick would be expected, but instead the graph shows a fall [in percentages] as the web has grown.
In short I don't buy that the ratio of the sexes in computing and tech is skewed by a global male conspiracy to suppress women as a realistic explanation.
[Aside, do you know of the study that they refer to in your citation, the results and anecdotes are mentioned but without citation?]
tl;dr see [+]