Why is the throat slash celebration in the nfl banned? ?

It's considered to be taunting, offensive, and unsportsman like conduct.  

Becasue it's offensive.

For the same reason the 1 finger salute is banned. It is offensive. 

Since OJ people have been a little touchy. The disembowelment of another player is also a 15 yard penalty. 

it's too graphic of images and violence should not be glorified. many children watch this stuff even adults don't need to see it! i for one find it disgusting!