I thought it must be some kind of gag. Until I got a few minutes into the movie and realized why the EPA felt the need to defend itself. I mean, it's silly - this is a cartoon! Would people REALLY believe the government would drop a big glass bubble over a town because it's polluted?
Of course not! We'd have to have people in charge who actually believe in things like global warming, pollution, energy shortages and the like!
Lighten up, EPA! It's the freaking Simpsons!