He literally just showed a video of her saying it had nothing to do with pregnancy.
She didn't say "it had nothing to do with pregnancy". She didn't explain why she left her initial job, she just said when she didn't continue in the education field. She just left the part about how she lost her initial job out.
Did you not read the articles? In April of that school year she had already been approved to teach the next year. Then by June, they took that away from her. THEN she went back to school to get credentialed after that. The claim that "it had nothing to do with pregnancy" and that she just needed to up her credential falls apart because they had already approved her for the next year without her upping her credential. In spots where they need teachers an emergency credential gets re-upped year after year, I didn't get my full credential until I'd already been teaching three years.
In the past sometimes she's mentioned getting forced out due to pregnancy, but often she didn't mention that part. That's because back in the day women were seen as the "weaker sex" and the possibility of them getting pregnant was seen as a big liability for employers. Emphasizing losing her job for being pregnant would have HURT women in the past because it would have emphasized what's seen as women's "weakness". It's only more recently that firing pregnant women is seen as an employer's problem and not as the woman's problem.