I agree the wages are absurd, but the fact is that Fox make an obscene amount of money out of The Simpsons, and it's only fair that a healthy chunk of that dosh goes to the people involved in actually making the programme.
It's the same with the football Premier League here in the UK. We have players that are paid £250,000 every week for several hours work (at most), and most people find that abhorrent. But that fact is that millions of people either pay the extortionate ticket prices, or pay Sky £50 a month in order to watch what these players are doing. All that money has to go somewhere, and it's only fair that a healthy chunk goes to the people actually playing the game that the public are will to collectively pay so much money to watch.
Whatever doesn't go to the people directly involved in the content ends up with someone even less deserving.
Of course, the people earning these massive sums could donate a large percentage of it to charity without even noticing. Feel free to blame them for not doing that :o)