So...
Student has no respect.
Teacher shows patience.
Student acts disrespectful.
Teacher tries to stay calm.
Student acts hostile.
Teacher tries to stay calm.
Student tries to take it on as an 'adult'.
Teacher decides to strike out.
I don't condone teachers hitting students but I don't condone disrespectful students either.
Couldn't vote, didn't feel it fair to say the teacher wasn't justified.