If every single reference to something that might offend someone somewhere was deleted from the Simpsons, there wouldn't be much left to show, would there?
Keep in mind that the Simpsons is supposed to be a show that reflects on society. You can't have a show that satirizes just about everything without referring to some "unpleasant" events. Besides, who's to say what's offensive and what's not? No one cares that there's how many movies about World War 1 or the sinking of the Titanic - no one gets upset (personally) by watching them. They're not touchy issues, maybe because they happened so long ago - but what should that matter?
Just because the Simpsons happens to be a little more up-to-date doesn't mean we shouldn't be able to see the WTC intact, or an obscure reference to something that hadn't happened yet (the Columbia) in Homer crashing a rocket.
Wasn't Deep Space Homer based on the events of Apollo 13? Even though lives were in danger there, no one seems to mind that being portrayed. I don't think every little reference needs to be taken literally and certainly no one should feel that the Global thingie is trying to offend anyone.