Sylvanas burned Teldrassil, which was filled with civilians - like a lot of them - and not very many military targets, and did so to try and break the Night Elven spirit. I’d say that’s pretty close to genocide.
I’m also talking more about Garithos. He wasn’t a great person, but he upheld his end of the deal he and Sylvanas made and she killed him. She also killed her own people for wanting to rejoin their loved ones.
She has a deal with the Jailer. Pretty sure that costs a lot of souls. She also specifically says even her loyalists served their purpose and were going to die anyway.