I find it implausible to believe that all this really had no effect on the impression that women were not the typical congress person, firefighter, etc.

For sure getting rid of those sorts of terms (my headscratching at OP aside) certainly pushes things more in the direction of gender neutrality, not less.

One girl closing off a career path for herself because she's noticed and internalized "-man" in the name is more than enough reason to adjust how we use the language IMO, and I have no doubt that far more than just one girl was impacted in such a way.

OTOH, I think there was plenty of very overt sexism back then that was going to have an effect that would likely completely eclipse the effect of the language in this regard.

So I think it’s a spectrum, and I believe you that you personally used it in a gender neutral way, but I doubt it was truly gender neutral in society overall.

I can't argue there, and if nothing else it was something to reach for when the typical folks (you know the type) would want to say "it says 'Fireman' right in the name!" or etc.

Edit: I essentially mismatched the quoted bits with my reply to each, fixed now. I semi-seriously blame cognitive weirdness post-covid.