This is the result of making clickbait, if what you're saying isn't really what you're saying, then expect people to call bullshit. "We don't know how many endings there are" is pure bullshit based on them trying to increase the hype even more. I get it, they want to sell their game, and saying "Well, there are 10 possible endings to the main narrative" isn't quite the same as 17,000, but don't get annoyed if people call out the exaggeration.
In my opinion, if there is really 20 totally unique endings to the main story, that will be incredible.
Nobody is making clickbait...jeez. Calm down for two minutes. The 17k figure isn't a lie but it also doesn't say what you immediately assumed it said either. Not to mention that no reasonable person would make that assumption either. The 17k permutations is a fact meant to illustrate how much reactivity the game has. And no matter how you slice it this game will still have by far the most endings than any other game ever made...whether you want to count it by unique endings or small permutations.