I acknowledge that the line he's citing is one wholly up to DM interpretation. The interpretation I gave is not "my own interpretation". I was merely listing other possibilities.
Arguing undefined rules is akin to arguing Rule 0, or building houses on Tapioca Pudding. There's no ground to stand on if you say "I'm right".
The only right answer is that the individual DM is responsible for determining what "generally" means.
Why? Because there's no RAW interaction between the Hide skill and spotting the presence or absence of invisible characters within 30 feet.
The RAW application of Spot/Hide interaction is thus: Spot < Hide? You don't see em. Otherwise, you do see them, and know where they are.
Any speculation beyond that is just that. Speculation. Which has no bearing in a "how things work" discussion.