Exposure Settings

Used to criticise people who told me that they were using manual settings with exposure compensation. Now realised that on manual mode, there is setting of aperture and shutter speed and the camera would show the exposure compensation value on the screen. So it is a miscommunication, as I do not know exactly what they mean. Logically, I was thinking that as they set the aperture and shutter speed, why there was a need to set exposure compensation.