Likewise I’m not convinced that I’m the one who needs to provide proofs in this discussion. You already said that “we” model genetic variation as being “random”. And the model is working great. Therefore it is only reasonable to assume things work according to the model unless proved otherwise. A model doesn’t need to be 100% correct to make correct predictions. We still use Newton’s physics model to predict things (flawlessly) even tho it’s not a “truly” correct model.