I had a feeling that was what you meant, but that's not how I read "the cube" in his posts. I read that to mean
his cube. If anything, I find it considerably more pretentious when people say "such and such is true in cube" without the "the" (implying to me that this statement is true of all cubes), when at this point in time there are so many different cube metas that aside from very black and white statements like "ancestral recall is good", you really have to consider context now. Maybe you could do this 5 years ago when everyone was running close to the same lists, but not anymore.
And this is only going to be more and more true as more cards are printed too. While comparing rare cubes isn't quite as diverse as say comparing legacy vs standard, it's probably more appropriate to think of card selection and performance in that way versus thinking all cubes are fit into a single format like modern or something.
The first thing I do when I see someone push a card or say such and such card isn't good enough is I try to find a link to that person's cube. What environment did they experience those cards in? It's considerably more valuable in that context. If I said
Dreadbore was rubbish, you might be confused unless you knew I didn't run walkers (which makes dreadbore unconditionally worse than terminate). And that's really not an extreme example. Some guys run aggro dominated metas. Everyone loves aggro and it is heavily enabled in their cube. Slow cards that are overpowered are not a problem in those environments. In mine (where the games are much more midrange), some cards are ban worthy that in other cubes aren't good enough to make lists.
Anyway, that poster provides a lot of in-depth information on how his meta works and you can get a lot of information by reading through it, looking at his list, and understanding how he cubes (he has this strange B and C cube thing where I think guys can take cards from those pools to round out decks similar to what people here do for utility draft). One card this guy turned me on to a long time ago is
Death Cloud. That card is an amazing finisher in a heavy black deck. You might think it's only good in MBC, but I play it in anything Bx that will get to three black mana reliably because it has a million and one uses. I never would have given that card a second glance without this guy's blog because it is a card that has been completely ignored by the rest of the cube community.