Pfft! Smart aliens just send a couple of stealth probes, figure out our biology, and in short order program a simple virus that is dormant but highly contagious

Pfft! Smart aliens just send a couple of stealth probes, figure out our biology, and in short order program a simple virus that is dormant but highly contagious for about a year and then when incubation is over kills within 24 hours. Ironically it’s not far off what was done to the Americas. War is only an option when the sides are more or less evenly matched. We would not be anywhere near evenly matched with an interstellar civilisation.