Interesting. I actually don't think we are disagreeing on the matter of intent, but merely talking about two different sets of intentions. I agree that there has to be a specific cultural/ethnic/class group that one is targeting. Which is the intention that you are referencing. The intention that I was referring to is one of goal. That the mass killing does not have to be intentional to be genocide. If I were to intentional expose everyone in Iceland to Compound X, and that resulted in a near extinction, I would be guilty of genocide. Even if my intent were to save everyone from Dread Disease Y. The judgement of others might be mitigated by my intent, but it would still be genocide.
I don't know what country you are in, but here in the US, murder is necessarily unlawful and malicious. Though not necessarily planned. If someone in a dark jumper and stocking mask broke into my home shooting at me, and I deliberately killed them, I would not be considered guilty of murder. Not unless they were a cop, or I was black or trans.
I would also point out all the places in the world both now and throughout history where someone of a "high" class can kill someone of a "low" class with impunity.
Which is why I say that, Genocide is the killing or attempted killing of a people group that potentially causes their extinction.
BTW, I would not limit it to people groups. People groups are just what we are primarily concerned with. Being people ourselves