It wasn't Rotenberg who gave him the nick, but fans.
There was an episode in the series where they played hockey. And Electronic was a cyborg who looked exactly as a kid named Syroezhkin so they dressed him to play instead. He obviously had superior skating and stamina to young kids, the problem was he still was a robot so he shot the puck by the most optimal trajectory i.e. the shortest one, and the opponents goalie saved all his shots with ease.
Of course Buchelnikov isn't a robot and can shoot very well, but he's fast and relentless and even looks kinda similar to that series' main character that's why Electronic.