Of course it's impossible for humans. Humans are used to clicking multiple times to do an action. Some actions you want to take in the game are very important, failure to do them correctly can mean a lost game, for example moving units in combat properly. This means that it's better to spam click that action a few times to make sure that the button press is registered properly, because it is possible for button presses to fail due to hardware, software, and most often a coordination error. This means that essentially every player has a much higher APM than EPM, but it's really EPM that counts. APM itself is mostly irrelevant.