There sure seems to be a lot of unstable people in the teaching profession.
This kind of stuff and worse has been going on for years and years.

Substitute teachers don't have the training of a certified teacher. They lack the necessary strategies needed to effectively run a classroom of children. Which can be anywhere from 25 - 35 students. Most only have the minimum requirement(High School Diploma). Others have college degrees but have never taught in school before. Any time you have unqualified people with your children you can expect things like this to happen.