True, especially in western Kansas. Kansas City pop is about 500k and it looks like that area is decidedly Blue. What's interesting is that Wichita, pop approx 400k is decidedly Red along with basically the entirety of the rest of the State.
One would probably have to look at the make-up of all the red counties, get the No's versus Yes's votes cast, to really see if it was a Kansas City thing or a Kansas thing.
Considering a 59% to 41% count, that large of a spread leads me to believe it was not just a Kansas City thing, but a Kansas thing.
Edit - From 538:
Definitely more of an urban thing, though interesting to see a sort of mix out in the hinterlands.