I will say it until the end of time. The amount of people that feel like only having 2 characters left will "ruin the hype" are a vocal minority. Most people don't feel this way, and the people who do will probably get over it. With Ultimate being the way it is, it's not something to easily lose hype over.
The reason why the box theory is annoying is because of how it was treated as fact during the first week it was around, and if you didn't buy it, you were in denial. That kind of talk is bothersome, and hurts speculation. Granted, said talk is nowhere near as prominent now, but every once in a while, I bring it up because non believers that aren't toxic about it are lumped up in a category where we're overly optimistic, and are setting ourselves up for disappointment. And frankly, being described like that is kinda rude.
So, again. Most non believers don't actually care how many characters are left, because Ultimate will be great regardless. But the box isn't suddenly concrete decisive proof of anything, so please don't treat it as such.
Though, to any and all non believers that compare believing in the box theory to being a flat earther or some along those lines... You may want to think over some things.