Many people confuse majority Russian speaking with majority ethnic Russian. While the majority of Donbas is Russian speaking, this includes a large number of Russian speaking Ukrainians. The majority of the population actually identifies as Ukrainian, not Russian. Donetsk is 57% Ukrainian and only 38% Russian. Luhansk is 58% Ukrainian and only 39% Russian. I refer you to the 2001 census.
As for identifying Ukraine on a map, perhaps these maps could help to better understand the true ethnic composition of Donbas:
Share of ethnic ukrainians among the population of Ukraine, census 2001
Settlement of Russians in Ukraine according to the 2001 census