That would be overwhelmingly true of most non-developer contributors too: they maybe submit one feature request that gets brushed off and then aren't heard from

That would be overwhelmingly true of most non-developer contributors too: they maybe submit one feature request that gets brushed off and then aren't heard from again. The question isn't whether most members of a given demographic are successful in derailing things or not, the question is if non-developer contributors are disproportionately likely to be disruptive to the project. I don't believe that to be the case, but am open to examples that provide evidence in favor of the claim.