Casualties means KIA, MIA, wounded and captured. The number above however was always stated to be the number of KIA.
Analysts said this number could be seen as a possible maximum. The confirmed minimum is much lower because we can only access open source intel. The confirmed minimum also only includes Russians and not Ukrainians from So called LNR, DPR.
You are right. Those numbers are very high. But russians as a society don't seem to mind. As I said, they forced a lot of Ukrainians to fight in this war. They also send tens and tens of thousands of prisoners into the Bakhmut meat grinder. Lastly they send their poor to die first.miatof them from eastern or southern regions who are not seen as ethnic russians by a lot of people living in Moscow.
We will see a better estimate of the numbers in 10 years. For now I wouldn't be surprised if it will be about half a million dead or even more.
It's been a legit military target since it was build.