I absolutely agree with the article. I mean, multiverses are fun and a cool idea, and they often make for good stories and even interesting ways to get around the problems sci-fi authors face in different stories... one of my favorite sci-fi shows was Sliders, which dealt with the original idea of quantum mechanics creating a new world for every different possible decision.
But Horgan is right in that multiverses are scientifically immature. We do not have the capability to prove or disprove it. If a scientist falls back on the multiverse theory, he's basically given up and said "We just don't have the technology, yet!"
This is as irresponsible as a science fiction author creating Warp drive, teleporters, stargates, the Force, etc... But those are books (or movies!) and we love them for the places they take us! We're talking about the same thing happening in REAL science? That's ridiculous.
And I think that's a far more interesting point