The purpose of a standardized estimate is to allow meaningful comparison of one item to another. Vehicles are tested with the same parameters in order to make it an "apples-to-apples" comparison. With EPA estimates, you can accurately predict that a Honda Civic will get much better fuel economy, all else being equal, than a Hummer H2. You cannot predict that you will get 42 MPG (or whatever it is) just because that's the EPA estimate.
The EPA estimates have always come with a disclaimer which explains that your actual mileage may vary. That's because the EPA has no way of knowing what speed you will drive at, what pressure you will maintain your tires at, what altitude you will drive at, how often you will get your oil changed and your air filter checked, etc. There are lots of variables affecting fuel economy.
Breathless accusations of some kind of eeeeevil conspiracy are for drama queens who have nothing important to do. The EPA estimates were never any such conspiracy, but a standardized estimate meant for a more intelligent and less paranoid public.
In this case, the comparison to regular cars was flawed, the hybrid mileage highly inflated, which would lead people to buy hybrids instead of regular cars based on false information. It also gave people unreasonable expectations of fuel savings that they hoped would more than pay for the extra price of the hybrid. If the sticker says the hybrid gets 20 mpg more than the regular car and it really only gets 5 mpg more (regardless of what the driver actually gets in either, it's relative), you're screwing a lot of people.
Breathless accusations of some kind of eeeeevil conspiracy are for drama queens who have nothing important to do.
There's no conspiracy, just growing pains in dealing with hybrids.