When you say 'they', do you mean pro-Ukrainian Gov forces murdered 15,000 or do you mean fighting between Pro-Russian Separatists and Pro-Ukrainian Gov forces have resulted in 15,000 deaths?
Zelensky stated as much December of last year.
https://www.txtreport.com/news/2021-...HyWsckU9t.html
who shot down Malaysia Air 17?
No one is saying there aren't Nazi in Ukraine. It was a failing of Viktor Yushchenko during the orange revolution and a failing of Poroshenko. But it is not completely unsurprising knowing how the history of Nazism in 1930's Germany and the German Gov fear of communism/socialism.