Deep contemplation of technical problems while staring at a screen and talking to computers for hours on end often made talking to people after work exceedingly difficult
And some of us like it that way.
Also, if programming is solitary as you suggest, why do tech companies discourage remote work and insist on culture fit, team building, collaborative work spaces, etc.? Much more so than law firms.
I've heard the argument that somehow "actual coding is a relatively small part of being a software engineer," but unless you're a manager (of which there are many more women), the thing you're being trained for, the thing you spend most of your time doing, and the basis of how people perceive the profession, is sitting in front of a computer coding. You can describe any profession as people-oriented on the basis that one needs to work with others, but the key question is whether the basic activity of the job is a social one.
Regardless of whether the people-vs-thing distinction is significant or not, it seems inaccurate in a big-picture way to describe programming as people-oriented. Like, that's not what people mean when they draw that distinction.
[1]https://blogs.scientificamerican.com/beautiful-minds/taking-...