In the movies that portray villains, there are three possible directions of portraying the villain’s motives. It is proposing no reason for their behaviour; proposing a bad reason for their behaviour; and proposing a good reason for their behaviour.
We see the first in such movies as the 1990s film “Psycho.” The movie does nothing to investigate the reasons for the villain’s behaviour. He is just called a psycho, and that is it.
We see the second in most movies with such themes. The villain is portrayed as wanting such things as world domination, vast money that he does not wish to earn legitimately, or doing harm to other people. The reasons for this are a variety of sins – greed, power hunger, egotism, cruelty, sadism and more. The villain is portrayed as bad for genuinely bad reasons.
We see the third in any number of other movies. In these situations, the villain is a tragic hero. He is a good person who has gone bad for a legitimate reason. We see this for example in “The Devil’s Own.” The Brad Pitt character is an honourable man driven by interest in his people’s freedom, who watched his family murdered by English police. He is not a bad person. He is a good person gone wrong.
There is a place and time in real world for all of the above. Some people do wrong senselessly; others for bad reasons; and others still for good reasons. In either situation it is important to understand the real reason for the behaviour. That way such behaviour can be dealt with correctly, based on the motives of the villain. And each case can be solved based on its actual character, with correct redress on the matter.