Personally I'd say anybody is free to downvote stuff he doesn't like - this can mean badly written, badly researched and topics you really don't want to have on the site; Suspension of Disbelief is likely more ofen encountered when reading in-character questions making them more difficult to be well received
We've had some discussions about more difficult topics, such as brutally torturing people, about different methods to kill people, about methods to create a government that is a brutal dictatorship and lots of other topics that, while they are on-topic, might still not really leave you with a nice feeling of "This is what I want to see and read when I am on this site."
That's why I think the standard tooltips on the voting buttons about a question being well researched and useful are only two things that you might want to take into consideration - the other being that you simply don't like the question and don't want to see it on the site.
In your case some people might have felt that calling out Wikipedia as a brainwashing future company might not really be a nice thing to do. Facebook wanted to prevent the world from being consumed by an Eldritch Abomination - your question reads at first a bit like libel. Not saying it is, just saying it reads a bit like it and some people might not take kindly to this. After all we are here because we want to share knowledge, so you might have hit a sensitive spot there for some people. Yes, I see your message at the end of the post - but many people might not scroll that far.
Another thing is that in-character questions are a strange two-edged sword. Sometimes they work incredibly great - and sometimes your nice question turns out to be everything else but well received. You have a bit of in-character speech, but not too much - maybe you have just hit the 50% ratio of people thinking it's a good rate of in-character and people thinking it's too much? Maybe some people don't like in-character questions?
People should be able to vote however they see fit. If you like a question and think "That's a great question, because it's well-researched." or you think "That's a great question, because it's the kind of question I like to read." then by all means upvote - and if you simply don't want to see this kind of question then by all means downvote.
Of course this is not a call to go ahead and simply downvote all questions that are not your favourite tags - I am talking about stuff you find truly aweful to read (for example I didn't downvote the linked AI question, but I was close to that; it reminded me of a certain troll we've had on this site some time ago) or for questions you just feel very, very bad reading on the frontpage alone (torture, killing, rape, ...).
If you feel that a question is really bad because there is no way you could possibly stretch your suspension of disbelief so far, for example because you are a computer guy and someone is talking about deleting the internet or something like that then this seems to fall into the classic no research category. Imagine I said "Just imagine for a moment that all atoms in you body were replaced by molecules" - could you really say this is a well-researched question when I didn't even realize that molecules are made up of atoms and that this statement simply doesn't make any sense? Depending on the people who see such a question it might immediately get voted into oblivion.
Sometimes you are just in bad luck and hit the wrong side for some people. Popularity is a weird thing and never seems to work quite the way you thought it would work. Maybe people didn't like the style of your question, maybe people didn't like your topic, maybe people didn't like your phrasing, ...
All in all "Suspension of Disbelief" is a combination of how well an author can convey his world to me through his writing and in regards to the topic the question is about. And that is incredibly subjective and depends on style, topic and my personal knowledge in the specific field. If someone says they downvote because they couldn't suspend their disbelief far enough then in my personal opinion they just haven't looked at the real reason - style, phrasing, topic, ... - and they are just using one of the standard reasons for downvoting. They also might be really critical if they can't outright say that it was your style or topic, but that it was something intangible like their Suspension of Disbelief. I wouldn't do it, but if others want to have such high standards then okay.
I suspect that "Suspension of Disbelief" is a phrasing more often used when you encounter something that is written in a fictional style, as in that moment we are changing from reading a plain question and being somewhat scientific in our answering/asking mode to reading a fictional work for a moment - that's probably what makes in-character questions so extremely weird as you have to be a really good author and you have to find the right crowd when posting. Some people might use different measurements when reading in-character questions opposed to out-of-character questions.
When reading a neutral question you are not worried about the "Suspension of Disbelief" - that's the authors job at a later point. But when reading a story you automatically have to "Suspend your Disbelief" in order to be part of the world and you have to interpret that world to understand the question.
I liked your style. Don't worry too much about it. Bad luck, it will be better next time. (Probably... maybe...?)