'All X' vs 'All the X'

Question

I alredy read “All X” vs. “all of X” vs. “all the X”,  “All rooms” versus “all the rooms”,  and Difference between 'all' and 'all the', but I still don't understand what are the similarities and differences in more complex syntax? Please elucidate and elaborate?

Ngrams shows that all the reasons why dominates over all reasons why. Yet on p 165, Postwestern Cultures: Literature, Theory, Space, English Prof Susan Kollin, PhD uses all reasons why:

All reasons why queer public space—like a truly visible, thriving center—starts to matter deeply.

Answer 1

In your particular example, the explanation is that ellipsis (the acceptable leaving out of some predictable grammatical elements) is at work.

Here is what we can't see, but what most experienced/native speakers know is there:

We assume that several facts (let's call them Facts A, B, C, & D) have been given. Then,

[These are] all reasons why queer public space matters.

It means A, B, C, & D each serve as reasons. It's possible that there are others.

If we use These are all [of] the reasons, we mean that there are no additional reasons.