This image does not support your argument, it does the opposite. Kherson is in the South, the one marked 82.3% (in 2003). Yet still, those fleeing choose to go to Ukraine.
When the USSR dissolved, with 84% of electorate participating, 90% voted in favor of independence, including majorities in both Crimea and Donbas. The referendum was accepted by all countries, including Russia. The percent of people speaking Ukrainian, and % wanting closer relations with Europe over Russia, has only increased since then.
I'm from Kharkiv and spoke Russian my whole life. Everyone around me did as well. We still identify as Ukrainians.
@UkroTurk brought up a similar personal example since he was in Donetsk in 2014. There was never a majority seeking to join Russia in Russian-speaking areas of Ukraine. Continuing to argue otherwise while trying moralize Russia's behavior is absurd.