I am not surprised at all that she was fired for pregnancy.
I was fired from my first job when the insurance would not cover me because of a heart murmur. That was normal at that time, and pregnancy is much more common.
We also had to pay all medical costs for our first child because the insurance for the new company would not cover pregnancy within the first year of employment. The birth was at 11 months.
The lack of belief now is due to:
- Ignorance, people who don’t know history
- Laziness, people who won’t learn about history
- Stereotypes, assumptions based on beliefs based on hearsay ideas
- Stupidity, refusing to believe statements of people who were there
Sexism, as described here, falls nicely into category #3 or #4