Did you ever consider that maybe the way he handled it, was the way he thought it would be easiest on the girls? What could he have possibly gained by purposely firing them in a manner that would have made the whole situation even worse for them (and everyone else involved) than it already was?
While I agree that both situations were unfortunate it is a business and both girls chose to be in the business. And let's not forget that along with the bad came an awful lot of good as well. They both had many wonderfully positive and memorable experiences that they woouldn't have had had it not been for Martin and the show.