Why do men say hurtful things after you break up?

It's a defense mechanism. The man may (or may not) still have feelings for the relationship or the person in the relationship and to prevent themselves from getting hurt or feeling the emotions of the split, they verbalize hurtful things. This sort of reaction is not isolated to men alone.

Its not limited to men... but.... when people split, even if you are the person that broke up with the other, you still have feelings, so most people try to distance themselves from the other and the easiest way is to be nasty... it makes it easier to move on

Yea ok,it may be easier at the time but eventually you will be sitting with yourself and reality will set in..