Genocide is a specific thing. It's not the same as "unjust war" or "lots of killing". It's the attempted elimination of a people; a culture, language, religion, etc.

Not every war is genocidal; and some genocides are not wars (because they're internal to a state — e.g. the China regime's ongoing genocide of the Uighurs is not a war).

Some of the conduct in the Ukraine invasion has been genocidal, e.g. abducting Ukrainian children to Russia to be raised as Russians, for the purpose of eliminating Ukrainian culture, language, and identity. This is the sort of thing that e.g. the United States and Canada sometimes did as part of genocidal conduct towards the Native American / First Nations populations.

Some of the rhetoric of the Putin regime has been genocidal; e.g. saying that Ukraine is not a real country and that Ukrainians are just bad Russians.

When the US and allies invaded Iraq, the goal wasn't to destroy the Iraqi people; it was to replace the Saddam government. The rationale for getting rid of Saddam was false, predicated on war crimes that Saddam wasn't actually committing — it was an unjust war.

But it wasn't genocidal. That doesn't make it good, or acceptable, or nice. It makes it not genocide; just as if you were to punch me in the nose, that would be a crime, but it would not be the specific crime of burglary.

Again: "Genocide" is a specific charge. It's not just a word for "really bad behavior" or "evil war".