Grandma, I totally understand your frustration! It's hard sometimes to fight ignorance, particularly if you see a lot of it! I think it's going to take some time, before people start talking right! I really hope so!
I believe that a lot of maps are of Russian origin. I've bought one of Western Russia, Belarus and Ukraine that in the US not so long ago. (It's all in English) And it has Russian names for all Ukrainian cities!!! It has Lvov, as well as Belaya Cerkov, Krivoj Rog, etc.
What can you do!
Now, I tend to believe that it's one of the main reasons foreigners have Lviv/Lvov problems! I guess, they just do not know the diference!
On another side, language is just a funny thing in itself! I guess I will never know why English say Ukraine, when it sounds more like Ukraina in Ukrainian! Or why they use Moscow, when it sounds more like Moskva in Russian! And where the hell Warsaw came from? Ask any Polish to name his capital, and it's not going to sound like Warsaw!
Some people just refuse to pronounce those endings!