"Any" or "some" in various questions?

I'm wondering why I always hear "some" in questions, although according to English grammar there should always be "any". At least the one I'm looking at uses "some". For example:

Why are some organizations using X?
Are there any organizations using X?

Is it due to the different nature of these questions? Open-ended vs. closed-ended?

It is true that in general in English, 'some' is replaced by 'any' in negative and interrogative contexts. But it is not as simple as that: 'Some' can be used in interrogative contexts, and is then 'marked' as linguists say: choosing it rather than the default conveys some meaning.

I would disagree with kajaco about just what nuance is conveyed: to me the choice of 'some' rather than 'any' is meant to exclude 'all'. So

Why are any organisations using X

may be appropriate even if all organisation are doing so (though the question is perhaps a little unlikely if everybody is doing so); whereas

Why are some organisations using X

implies "and others are not".

"Some" implies we are looking for more than one. In your example, we want to know why some organizations are using the frobisher widget, when our experience with it has been terrible (for instance).

"Any" means, we are wondering if even one exists that meets the criteria. Carrying the example further, we want to know if any other organization is using frobisher widgets, or did they all switch to wozgood widgets because they're better.

I do not know what grammar you are referring to that says "there should be always "any"." I've never heard any such thing.