Following this reasoning, if there is a finite causal state machine, then your pruning operation would eventually remove me, you, the human race, the planet Earth.

Now, from inside the universe, I cannot tell whether your hypothesis of a finite state graph universe is true or not - but I do have a certain self-interest in not being removed from existence. I find, therefore, that I am scrambling for justifications for why the finite-state-model universe nodes containing myself are somehow special, that they should not be removed (to be fair, I extend the same justifications to all sentient life).