But chocolate bars don't turn into hamsters. The universe is predictable. Why are we discussing this stuff when we already know it isn't true?

Chocolate bars have a very low probability of turning into hamsters. A chocolate bar is one configuration of elementary particles, and a hamster is another, and there are lots of particles that may or may not be in the space of that chocolate bar at any given point in time.

Our universe is predictable, in that very low probability events happen with a very low frequency, but this does not entail that very low probability events never happen.