You mean you've never met any non-transhumanophile and/or non-SF-bay human? (I kid, I kid.)

Walk down to your nearest non-SF-bay starbucks and ask the first person in a business suit if they think we could ever simulate brains on computers. Wager you on >4:1 odds that they'll say something that boils down to "Nope, impossible."

For starters, the majority of devout religious followers (which is, what, more than half the worldwide population? more than 80%?) apparently believe souls are necessary for human brains to work correctly. Or at least for humans to work correctly, which if they knew enough about brains would probably lead them to believe the former (limited personal experience!). (EDIT: Addendum: They also have the prior, even if unaware of it, that nothing can emulate souls, at least in physics.)

Now, if you restrict yourself to people familiar with these formulations ("Whether human brains can be simulated by any turing machine in principle") to immediately give a coherent answer, your odds will naturally go up. There's some selection effect where people who learn about data theory, turing machines and human brains (as a conjunction) tend to also be people who believe human brains can be emulated like any other data by a turing machine, unsurprisingly enough in retrospect.