Halloween: The Curse of Michael Myers (1995)

Continuity mistake: Mrs. Strode's shoes change when she comes in the house from cleaning the porch and goes downstairs.

Sheriff: Go back to your loony bin. I've got enough problems around here without you stirring up ghost stories.
Doctor Sam Loomis: I suppose it was a ghost who did all of this, and a ghost on the radio last night, and a ghost being carried out of here now."

Trivia: The production of the film was notoriously troubled. There were numerous writers working on numerous drafts of the script before one was finally settled on. Filming was hectic with many scenes being omitted or re-written on-set. And after the first cut was complete, a poor test-screening lead to the film going through drastic reshoots that altered much of the story, including the addition of a brand new ending, which had to be written around the fact that co-star Donald Pleasance passed away shortly after the end of principal photography.

Question: I've seen this movie three times and there is still something that I don't understand. What exactly is Michael Myers curse supposed to be and why does this curse involve him killing his family and their friends?