It's not a blanket no toward questions like this. As the rules say, there is a case-by-case approach taken to "Why is ___ this way?" questions that fans can't answer definitively. Some have a straightforward explanation (water conducts electricity), while others have very good guesses that are worth knowing about (example, although even that question started to spiral).
The issue is a majority of "Game Freak logic" questions don't fit the purpose of this community, which is to give confident answers that serve as resources for people now and in the future. Unwieldy discussions that arrive at "the designers wanted it that way" are not valuable and not what we're aiming for. We know from many years of experience what questions are going to be like that (and where we don't, we wait for before closing).
Why isn't Ghost immune to everything? How does anything cause damage to an immaterial being? We can do this forever, and that's why it doesn't work on a platform that has answers not replies.
There are resources here showing where to go outside PokeBase if you find us unaccommodating.