[DiogenesKynikos]

> The claim was that inaccessible worlds are inherently incompatible with our ability to empirically investigate or falsify them

That's not what the claim was. The original claim was that MWI is "incompatible with our experience of reality." TheOtherHobbes then said that the incompatibility is that we experience only one reality, instead of many realities.

> MWI has a metaphysical parsimony to it. But to believe it's physics is religious faith not physical science- and that's fine, but it's still not science.

It's not religion to point out that QM explains the phenomenon of wavefunction collapse without any additional postulates (through decoherence). That's all that MWI says.