What it ultimately boils down to is the fact that a few of the aforementioned mods had it on good authority that the information they'd been tipped off about was valid material.
It turned out that it wasn't. It isn't the fault of the mods, because as far as they were concerned, there was no reason for it to be fake.
At the same time, it's a good testament to just how insubstantial hearsay and rumour really is. It wasn't deliberately spread as false information, it was just an unfortunate side-effect of whatever kink in the communicative chain caused the wires to be crossed in the first place.
The same is true of the Butt Butt rumour: we don't know anything for a fact. Absolutely nothing. Zilch. Di nada.
What we do know is that a few people whom are known to be reputable and trustworthy sources have good reason to believe it's true, which, when conflated with the confirmation of the Butt Butt amiibo (incidental to the original rumour, yet still intrinsically connected), seems to line up.
Whether it's true or false, we don't know. I personally urge caution in the matter. Precedent has demonstrated that both sides of the equation can turn out on top: we know that a leak can be totally verified and end up being confirmed mere days after the initial reveal (the Ninka and ESRB leaks), or it can just be an unintended hoax that causes more harm to the speculative community than good (the Spainkiller leak).
Butt Butt may be coming.
He may be the result of a profound error in communication.
What we need to do is entertain both eventualities, because this could really go either way, for better or for worse.
For the record, I am totally neutral on Butt Butt. I just think we as a community should know better than to take objective sides on a debate that we really don't know anything coherent about.