Look, if you believe people weren't manually doing that if they wanted then I have news for you. Now that they can do it automatically, possibly with just the click of a button, it really doesn't make much difference. Most people aren't going to cross-post comments because there'd be no context.
Then they're coming out with other scripts to 'disable' comment posting on their journal. Except all it does is hide the buttons from yourself. People can force it back or force their own style.
*shrug* Do what you will.