I'd say it's a possible manifestation of self-interest, but that it isn't always self-interest. There are people that hurt others without any apparent self-interest. When it gets out of control, we call them sociopaths or psychopaths. But that's a minor point.

My point was more that the dichotomy stupidity vs. malice seems to imply that e.g. playing music, or having dinner is either stupid or bad. Many things get done out of self-interest without being malicious, or without malicious intent.