When a bug is found in production, who's to blame? Is it the tester for letting the defect slip through? Is it the developer for introducing the bug into the code into the first place? Is it the analyst who neglected to anticipate the myriad ways in which the system could be used? Or is it the project manager who did not allocate enough time for testing?
Clearing trying to find fault is going to be neither helpful nor accurate. Once the blame game starts, everyone starts ducking and pointing the finger. On waterfall projects, too often the blame ends up focussed on whoever was last caught holding the bag, which is usually the testing team. Clearly there is an element of accountability on behalf of the entire team, but this fact is too often obscured by the need to find fault.