The word ontic makes it sound more esoteric than it is. In quantum mechanics, you could have a model that predicts everything you can practically know and calls the rest "random," or you could have a model with far more complexity and a lot of unusual internal mechanisms, that predicts everything you can practically know and explains the rest as not knowing the initial conditions. If you simulate quantum measurement on a computer, you're doing the latter - computers have nothing to do with nondeterminism, and would be choosing the results with a PRNG. "A PRNG decides everything between each step of the universal process," is an example of the kind of unusual internal mechanism that deterministic QM must have.
In classical mechanics these are the same model. So what is presented as physical evidence for metaphysics is actually quantum mechanics splitting apart two ways of looking at randomness, which classically are equally complex and hard to tell apart (thinking of the future as a probability distribution vs. believing that the future is a definite point about which your knowledge is described by a probability distribution), but in quantum mechanics are not.
In classical mechanics these are the same model. So what is presented as physical evidence for metaphysics is actually quantum mechanics splitting apart two ways of looking at randomness, which classically are equally complex and hard to tell apart (thinking of the future as a probability distribution vs. believing that the future is a definite point about which your knowledge is described by a probability distribution), but in quantum mechanics are not.