They can’t just be making shit up and basing stuff on that
I mean, at least for the publicly available numbers, they literally can. Not to mention, Ukrainian estimates for war casualties would almost certainly be completely wrong because the Ukrainians have been continuously pushed back for over a year now. How would they even measure Russian casualties? Their frontlines are lacking manpower and they are disadvantaged on the electronic warfare front.
I mean, at least for the publicly available numbers, they literally can. Not to mention, Ukrainian estimates for war casualties would almost certainly be completely wrong because the Ukrainians have been continuously pushed back for over a year now. How would they even measure Russian casualties? Their frontlines are lacking manpower and they are disadvantaged on the electronic warfare front.