why are automatics so messy

Now a days dealers or jiffy lube just hook their machine to the cooler lines and tell you they flushed the tranny. I know I am not the brightest person but I think that is BS because the old filter is still in it. My wife's 300c doesn't have a tranny dip stick. I questioned dealer about buying one and they told me that this is a dealer service item. Right can you say Ebay.