I'm going to be honest here - I'm not comfortable with the tone of the OP post, with words/phrases like 'this kid' and the word 'awful' used several times. We have no idea why this boy behaves this way. What if this child has a perception or auditory problem? He can't control himself but what if its not his fault?

Yes I agree he should be disciplined and if he can't be controlled, then removed from the classroom. I'm not saying what he did wasn't wrong. Unfortunately kids this age can be a handful with hitting, bad language and aggression. A boy told my 8 yr old daughter "I want to have sex with you". Like I said before this boy might have home problems or the boy might have control problems. I'm sure many people were a handful when they were kids.

I agree it wasn't right to throw a knife at another child, but I'm wondering if this was a plastic knife - most schools are forbidden to keep real cutlery in their schools. Again kids throw stuff at each - sure it's not right but it's not shocking. I think all children even misbehaving ones deserve compassion as well as discipline. Also there are parents who are great but have misbehaving children - autism/ADD/ADHD/learning disabilities. It's easy to dislike a person, compared to figuring out why they act out. A skilled teacher is able to relate to all students good and bad IMO. This is why Super Nanny is so respected - she can see the good in a child who's misbehaving.