Here are two ways you could go about digesting the idea:
1. Think of it less like a game jam, and more like a music jam. We're just getting together to play around with ideas inside a wide possibility space, and every year fun and colorful things happen, which makes us happy.
2. Every medium, every genre, every art and type of craft has movements within them that explore and challenge the boundaries of its definition. We're like the slow TV of game jams. We're the Jackson Pollock of game jams.
In any case, it is what you make of it. There is a start and an end date, and many of us try to submit before the deadline, as a creative constraint in traditional game jam fashion.