It's really sad to see that most of you have also experienced something similar...

I had a religious freak (catholic) for a teacher when I was in the 4th-5th grade, and she would also use a ruler to slap our hands (nothing like in this video though). It might have been more socially acceptable back in the day, but it was still abuse if you ask me. These are merely babies, that should be singing the ABC's...
My wife is a teacher herself as well, and when she saw this video, she literally started crying and walked away from it.