It's because most of the time people see mostly powerless people trying to do their jobs and messing up. They don't have as much of a frame of reference for how powerful people act, especially because there is so much mystification in the media (literally owned by the said powerful people). The rule you apply to your friends and co-workers isn't suitable for the maniacal supervillians running society. Of course, those guys also fuck up in bizzare and stupid ways too, so people will point that out and be like look, they're just bad at their evil jobs!