An explanation that says all observations are equally likely is hard to disprove and hence hard to gather evidence for by conversation of evidence, but that doesn’t mean we should give it an extra penalty.
A straw Popperian could say that the hypothesis “flipping the coin provides random results” is unscientific, because it allows any results, and thus it cannot be falsified.
A straw Popperian could say that the hypothesis “flipping the coin provides random results” is unscientific, because it allows any results, and thus it cannot be falsified.