I'd much rather know WHY something is or is not happening

Jeez, I just told you "why":

because all their energy was focused on HoT

It's not because it isn't the "why" you want to hear that it's any less of a justification.

It seems like your reasoning lacks some shading. From your wording, they should tell us everything because you dislike the opposite. What about a middle ground?

I don't understand this will to have Anet tells us everything when it's not needed. In the end, so what if they don't go into details about SAB for example, will it prevent you from playing? Will it crashes your client? Will it give you nightmare? Does it break the game? If all the answers are "no", then your dislike of the secrecy is purely motivated by a high curiosity on your part, it has nothing to do with a necessity.

What we need to know is already being told. SAB? They're focused on HoT. Dungeons? They told us they had different plans in the future. New implementations? We're getting blogs weekly to explain the new systems. Their future plans? They always tell us in due time when everything is ready to be revealed to prevent disappointment. Every small bits of info they've revealed about HoT so far will make it into the game, unlike the famous precursor hunts that was announced years ago which lead to major disappointments.

So any other type of information is purely optional.

Quite frankly the only thing I agree with you is the undocumented fixes and updates. For anything else, we shouldn't more than the minimum. And yes, they have every reason to not trust us. Just look at the April fool: a small joke turned the forums and this reddit into a 24 hours of drama. Anything they bring to the game create a shit storm of ugly posts. If I were in Anet's shoes, I wouldn't trust players at all. We're quite disgusting and annoying to be honest. We've proven countless of times that even the smallest piece of information can generate drama.

I don't blame Anet for their secrecy, we don't deserve otherwise.