I've read: Difference between Xはどこ and どこがX.
I understand the top answer but I'm unsure of the "why" for why those two statements mean differently.
They say that (A) is when the speaker has little idea of where the hospital is, or if it even exists while (B) assumes knowledge of a hospital. What part of the structure gives them this difference? I've only been learning Japanese for two weeks so I'm still pretty foreign to this. Is (A) structure used more? It's consistent with what I've learned like "nan desu ka".