Cool avatar. I hear the KFC gut version is about 5 times that size.
There's nothing wrong with grunting. There is something wrong with being an ass and yelling at the top of your lungs just so everyone notices you more.
There are places you can yell (like a powerlifting or hardcore gym where everyone is very serious and cheering each other on), but the average public gym today isn't the place for it.
Also, if you are pressing a very average weight yet screaming out loud, you look like a douche. If you are going to be making that much noise, at least have the decency to be pressing some serious weight.