How could it not imply it? That's when women started entering those fields en masse and really increasing their numbers. Going by the "the problem is men being sexist" reasoning, that they were able to do this successfully implies that the lawyers and doctors in charge then were less sexist than engineers today.
I don't think the field is sexist. I think fewer women choose to study and excel at it. The field is open to whomever wants to have a go at it. Due to "corporate diversity policy" I think (as a man) have less of a chance of actually breaking into software engineering than, say, 10 years ago.
I mean, that doctors and lawyers were substantially less sexist compared to engineers in the 60's and 70's also strikes me as less than plausible, though I'll grant that'd be a closer competition than comparing them to engineers now. Do you have any evidence of an advantage there?
But the 60's and 70's are when the representation levels started really diverging. That's the key part.
That they may be less sexist now, after having achieved gender parity or something close to it, is hardly unexpected. Of course a field with roughly even numbers is usually going to be less sexist than one dominated by one gender or another.
You'll have to spell the argument out. My claim is that relative sexism in STEM puts women off now. This does not require me to commit to the claim that relative sexism was a dominant factor in women's career choices in the 60s. Note, however, that the issue is sexist attitudes in society as a whole, not just engineers being sexist. Even if 60s lawyers are just as sexist as 60s engineers, the idea of a female lawyer (especially a junior one) may still be more socially acceptable.
Asserting that a gender balanced field is less sexist than a gender imbalanced one isn't very interesting. The interesting part is that law and medicine used to be just as gender imbalanced, and then steadily became less so.
This is the crux of the issue that you're avoiding grappling with. Saying "well I don't care about the history" is irrelevant, it's still the most important part whether you personally care or not.
It's like looking at which countries are desirable to immigrate to without grappling with patterns of development, despite the obvious fact that the biggest thing that makes countries more desirable is being rich/developed.
Measuring these things by outcomes is always wrought with errors. For example, how do you compare women's interest in medicine 50 years ago to their interest in comp sci today? If raw interest is low even a trivial scale issue might dissuade you.
It's also dangerous to treat all software development the same. I'm my experience women tend to be more interested in human facing parts of software like web and ui development, but less interested in the back end parts. Is this the result of sexism? Maybe, but regardless I bet the gender stats are very different if you consider front end as different than back end development.
