WTF? Old lady with Soviet flag mistakes Ukrainian soldiers for Russians, soldier makes fun of her?

I get it that Ukrainians are unhappy or angry with the Russian invasion and with Russian soldiers, but what’s the point of annoying an old couple, who didn’t even have a Russian flag, but a Soviet Union flag? (The Soviet Union included the Ukraine.). I’m no fan of Soviet Communism, but still, it’s weird. I felt bad for the old lady returning the food… It's too sad that things reached this point, where Russians and Ukrainians can't be friends anymore?

NOTE: I usually don't like to post these types of unverified videos, as they could be FAKE, but: a) this one appears to have been uploaded by the soldier himself (according to Gonzalo Lira); b) it's not really graphic or very serious, I guess he just thought he was being funny or making a point about "this is my country, Russkies". No info on where or when it was filmed, nor if the translation is accurate, sorry.