No, it's not juggling. It really is logic. Logic is merciless.
I'm not saying what you're saying I'm saying. You seem to have an extreme position, and to be assuming that everyone who disagrees with you must be taking an equally extreme position, only opposite. But that's not it at all. Your position is extreme. It's untenable. It's inconsistent and illogical. At least, the position you seem to me to hold is all those things. If I've mistaken your real position, then this discussion has a point.
You seem to me to want to equate unproven with false. I disagree, but I do not want to equate unproven with true.
My point is that it's a trivial consequence of actual logic, through the axiom of the excluded middle, that if unproven means false, then undisproven means true. So I'm certainly not saying that anything that isn't disproven must be assumed to be true. It's precisely my point that that statement is exactly equivalent to the one that you made, which I oppose. So my point is that both positions are logically untenable.
If something is unproven and undisproven, then nothing must be assumed about it. Anything may be assumed about it. The jury is out. All bets are fair. All positions are tenable.
You offered to accept the formula, for something unproven, "It's possibly true but unproven." Perhaps that might be okay, but then it seems to me to follow trivially, through the axiom of the excluded middle, that you have to say for anything not disproven that you can't call it false, but only call it "possibly false, but undisproven."
I would still say that it has to be wrong to call someone insane just for believing that something is true even though it's unproven. Consider Fermat's Last Theorem. Up until 1995, this was an unproven statement. It stood unproven for over 300 years. But it would be strange to say that the statement was ever false, because it has now been proven and is known to be true. I'd rather not say that it only became true in 1995. It's a statement about arithmetic and I don't remember arithmetic changing suddenly in 1995. Many fine mathematicians, from Fermat on, believed that the statement was true, before it was proven. I don't want to call them insane. They were fine mathematicians. And concerning this particular statement, in fact they were right. If you can be insane by being right, then maybe what we need is more insanity.
Now, all of the above is what's relevant for me, if someone tells me that they happen to believe something. If I can't disprove it, then I can't call them crazy for their belief. But if someone tries to tell me that I must believe something, then I'd agree with you: if they can't prove it, they've got no business telling me what to believe. It's precisely that to which I'm objecting, when I object to what I find to be your extreme position. You seem to be telling me I can't believe anything unless I can prove it. My point is that you can't prove that, so get off your high horse. But if all you really mean is that I can't tell you what to believe unless I can prove it, then in fact we agree.