This case seems to be a bit different. She has a state certification for grades K-3, and a National Board Certification for ages 7-12. Assuming that most start kindergarten at age 5, this covers her for all but the most extreme cases. She also started the year in 2nd grade, and the administration moved her to 5th grade.
Where I live in NC, there are many teachers leaving the profession because it's just not worth the hassle, or they simply can't afford to keep teaching, or a combination of both. I can't imagine it's much better in AL. Why bother working at a job where you're consistently undervalued?
I see this as a "last straw" situation. They've pushed her over the edge and she's tired of the hassle.
It's unfortunate, though not surprising, that the the kids get the short end of the stick as a result of the stupidity of the adults who should know better.