Well you are citing a HIGHLY unscientific and invalid poll.
For instance this:
"Amongst the "Yes, I think MWI is true" crowd listed are Stephen Hawking and Nobel Laureates Murray Gell-Mann and Richard Feynman. Gell-Mann and Hawking recorded reservations with the name "many-worlds", but not with the theory's content. Nobel Laureate Steven Weinberg is also mentioned as a many-worlder, although the suggestion is not when the poll was conducted, presumably before 1988 (when Feynman died). The only "No, I don't accept MWI" named is Penrose."
Gell-Mann does not support Many Worlds and he never did, he is a proponent of something called Consistent Histories. Stephen Hawking is not a supporter of MWI either, it was taken out of context in a interview, he has later cleared this up. I have personally asked Steven Weinberg and he says he has changed his position due to the probability issue, he actualy mentions this in a interview from earlier this year, but more importanty in his most recent paper from somewhere around Sept-Oct.
The author of that FAQ has an almost religious view of MWI, he is still weekly updating the wiki site and it seems his best arguments are an appeal to authority, which I've just shown is a false authority as they do not share his views.
Even David Deutsch, the strongest proponent of MWI, admits that he estimates that less than 5% of those working on quantum foundations accepts Many Worlds and within that group there are atleast 10 different "many worlds" views that are at odds with each other.
As for the Born Rule paper, well I have certainly never heard of it before, if it indeed was a vaid derivation of Born Rule within a Many Worlds context I am pretty sure it would be huge news within the foundations community, which it has not. It is listed with a "wavefunction collapse" tag, so I doubt he is talking about Many Worlds.
More polls on the topic are listed here.
By now it looks as though you don't have much good evidence for your claim that "the vast majority who think these issues through definitely reject MWI".
The subject has already been raised in this thread, but in a clumsy fashion. So here is a fresh new thread, where we can discuss, calmly and objectively, the pros and cons of the "Oxford" version of the Many Worlds interpretation of quantum mechanics.
This version of MWI is distinguished by two propositions. First, there is no definite number of "worlds" or "branches". They have a fuzzy, vague, approximate, definition-dependent existence. Second, the probability law of quantum mechanics (the Born rule) is to be obtained, not by counting the frequencies of events in the multiverse, but by an analysis of rational behavior in the multiverse. Normally, a prescription for rational behavior is obtained by maximizing expected utility, a quantity which is calculated by averaging "probability x utility" for each possible outcome of an action. In the Oxford school's "decision-theoretic" derivation of the Born rule, we somehow start with a ranking of actions that is deemed rational, then we "divide out" by the utilities, and obtain probabilities that were implicit in the original ranking.
I reject the two propositions. "Worlds" or "branches" can't be vague if they are to correspond to observed reality, because vagueness results from an object being dependent on observer definition, and the local portion of reality does not owe its existence to how we define anything; and the upside-down decision-theoretic derivation, if it ever works, must implicitly smuggle in the premises of probability theory in order to obtain its original rationality ranking.
Some references:
"Decoherence and Ontology: or, How I Learned to Stop Worrying and Love FAPP" by David Wallace. In this paper, Wallace says, for example, that the question "how many branches are there?" "does not... make sense", that the question "how many branches are there in which it is sunny?" is "a question which has no answer", "it is a non-question to ask how many [worlds]", etc.
"Quantum Probability from Decision Theory?" by Barnum et al. This is a rebuttal of the original argument (due to David Deutsch) that the Born rule can be justified by an analysis of multiverse rationality.