The so-called "fat cat" charge that easyjet pass on to customers is the Passenger Service Charge that all airlines have been cashing in on. Basically, the government decided that the PSC (which has always been included in the ticket price) had to be shown separately on the ticket. easyjet and everyone else have taken the opportunity to lump it on ABOVE the ticket price and therefore make a few extra quid per sector.
Stelios is such an ace at publicity, he has managed to convince people that he is "on their side" whilst charging them more for their tickets. Clever bloke!