From replication of the experiment the figure's more like just 30% refusing after a certain point. In any case, being happy about 30% or 50% is a weird way to see things. "Sure, at least three billion humans are willing to follow insane orders from an authoritative figure they only know by authority (not by actually liking them a-la Hitler or fearing them), but the rest of us aren't quite as susceptible under these exact conditions!" It's like being happy that only 40% of Delaware voters voted for O'Donnell.
Also, does anyone else feel like the subject's (Man Two's) lines were scripted, or did people talk that way often back then?
Edit: replier is right, 'most insane' does not fit here.