There are other ways to combat illogical ideas.
As an atheist I would not fire people for being believers (even if it were lawful to fire on that basis) --just because "I know better". If one of them tried proselytizing, by law I can't do anything about it, but even if I could, there would be better ways to combat irrational appeals and sowing of fear.
That said, what if the engineer has "only" presented the ideas as a private person at a "men's club"? If that's not okay, then this infringes upon people's speech outside of work as a citizen --that's chilling. There are Walmarts out there.
I believe in making tech an attractive career path for women --as a society we underutilize them and don't extract the value we could --as the soviets did from their women. But at the same time, I am sensitive to kerbing speech.