Reality does not care who has the burden of proof, and it does not always provide proof to either side.

If I'm only willing to expend a certain amount of effort for gaining understanding of a given aspect of reality, then I won't listen to any explanation that requires more effort than that. Preparing a good explanation that efficiently communicates a more accurate picture of that aspect of reality is the burden of proof in question, a quite reasonable requirement in this case, where the topic doesn't appear terribly important.