You seem to assume that MWI makes the Sequences more vulnerable; i.e. that there are people who feel okay with the rest of the Sequences, but MWI makes them dismiss it as pseudoscience. I think there are other things that rub people the wrong way (that EY in general talks about some topics more than appropriate for his status, whether it's about science, philosophy, politics, or religion) and MWI is merely the most convenient point of attack (at least among those people who don't care about religion). Without MWI, something else would be "the most controversial topic which EY should not have added because it antagonizes people for no good reason", and people would speculate about the dark reasons that made EY write about that. For context, I will quote the part that Yvain quoted from the Sequences: [...] Everyone please make your own opinion about whether this is how cult leaders usually speak (because that seems to be the undertone of some comments in this thread).

Actually, I can probably answer this without knowing exactly what you mean: the notion of improved Solomonoff Induction that gets him many-worlds seems like an important concept for his work with MIRI. I don't know where "his work often gets ripped apart" for that reason, but I suspect they'd object to the idea of improved/naturalized SI as well.