Think of the total logistics of a global genocide. It's not just making billions of death jabs. You also need to have the gulags for dissenters, the trained staff, the "marketing collateral" (to all audiences), the surveillance systems, etc. — and throwing the timeline off upsets all of these. They couldn't reconfigure their assets to deliver the killer blow to humanity fast enough. Now we just have to make sure they take down the minimum possible number of us, leaving as many standing as possible to rebuild.