I am not 100% sure about program mode, but it actually seems pretty useful for some people. If I am understanding it right, what it's doing is saying "for x amount of light, you can get all these exposures" meaning, as you dial through the options, at one end you'll get the maximum shutter speed/minimum aperture and at the other you get maximum aperture/minimum shutter, wile maintaining the same exposure value for the given meter reading.
While Program Mode isn't for me, mostly because you can't teach a middle-aged dog new tricks - I think it does get a bad wrap.