To me, the issue is that Strasbourg is close to a larger and better known "S" city. Savannah isn't exactly a world metropolis, but there aren't any other "S" cities in the vicinity.
Remember, you can zoom the map by clicking it. The fact that the dot lies on the border is a dead giveaway because Stuttgart is right in the middle of Württemberg.
Strasbourg is where the European Parliament is based, so from a political perspective it's more well-known than Stuttgart despite being smaller in population.
Strasbourg is, among all other things, one of the seats of the European Parliament. Sendai and Surat are just two of those huge bunch of cities in Eastern/Southern Asia (slight exaggeration but you get the point).
Not sure how I missed Shanghai. Got Shenyang though by guessing random Chinese names. Also I think Stuttgart should be accepted. It is the inky 's' german city I know
You included Strasbourg, which is barely a village, but not Stuttgart.....
What about Sfax, Tunisia's "second city"?
What are sendai and surat known for? Does not ring the slightest bell.
...And it's even more bizarre to see how many of them seem to think that's a problem with the quiz!