Go to https://www.icty.org/, read about cases, verdicts and pleas:
https://www.icty.org/en/cases/key-figures-cases care to search for the GENOCIDE word in there?
Serbia did bad the things in Slovenia, Croatia, Bosnia, and was going to do the same in Kosovo until NATO bombarded them. (Kosovo was already critical in 80ies)
That doesn't absolve any party of the commited (war) crimes, but it is perfectly clear who was/is the regional bully and who commited aggression against neighbours.
I also don't buy tipical lines "they all hate each other", or this is the revenge for what " they" did to "us" in WW2, WW1, during Ottoman times, during Roman times ... Historical crimes are not excuse for new ones, vicious circle must stop somewhere.