This feels like trying to explain to someone that you can have 2 different infinities, and one is larger than the other. Both are bad, but one is clearly worse.

"What's the difference if you end up at the same place?"

The difference is that 2 genocides is not the same place as 1 genocide. It is reasonable to criticize the people supporting a genocide while at the same time recognizing that the people wanting more genocides are not the same.