Is it normal to assume everyone is from where you are?

Its weird that there are people on here that assume everyone is from the same state, province, country, city. When someone asks for advice they will state stuff based specifically on where they are from. I find it kind of sad how stupid people are. I am a US citizen I dont assume everyone is from the same damn city I am. What the fuck is wrong with people? Like if you live in LA they assume you live in Newyork city and they dont understand what the difference is. Well for one thing one of you is from LA, why the fuck would you assume otherwise unless already stated?