Come on guys, look at the episode title. If that was no clue something was going to happen, take into mind that airing it 2 weeks after April 1st is the real surprise. A joke is a joke, but I can understand you guys hating it. Most shows that do something like that get hated on for a while. Just wait, we might see a crossover in 4 weeks.
Oh, is it ok to mention South Park did the same thing 13 years ago? Well, the same reaction occured, but the internet was not as big, so they got telephone calls instead. And Not Without My Anus was actually really funny, and I am sure this episode is too (sorry, I didn't watch it, I just heard it was an April Fools thing).