Maybe it's true, still, if you don't understand, it doesn't mean it's the case for others.
During WWII, Ukrainians from villages who never learned Russian were sent to Russian-speaking groups and they could communicate with each other well.
I know a guy who moved to Kiev, he said he didn't have much problem with understanding people and signs on the streets.
As for me, I've even watched a tv show in Ukrainian and I used a translator only 2-3 times, the rest of the time, I just had to listen carefully to comprehend better.
And yeah, was that necessary to shittalk? I just shared my thoughts. You are implying that the experience of mine other people is not real, which is ridiculous