My family comes from Red Ruthenia, region where ruskie pierogi comes from. Because of lingual characteristic they are usually linked to Russia (as mentioned in article) and so, with all the turmoil many restaurants decided to rename them: either to pierogi with potatoes and cheese or to galicean - as from Galicia, which is commonly perceived as Krakow (due to it being center of the region).
Krakow doesn't have as good pierogis (but there are other things worth seeing and eating there though) and is half-the-Poland away so it feels to me somewhat like a takeover of a legacy and stings. So if you ever have a chance - go visit Lublin or even smaller cities like Chelm or Zamosc. Food is absolutely terrific there (which I guess is thanks to charnozem soil [1] in the region).