Is not the purpose of weapon of mass descruction to destruct as much as possible? This includes not only cities, factories and civilians, but for example, pollu

Is not the purpose of weapon of mass descruction to destruct as much as possible? This includes not only cities, factories and civilians, but for example, polluting soil with radioactive materials so that it becomes unusable for living. Don't forget that civilians are potential soldiers, guerilla warriors or military factory workers so it doesn't make sense to leave them alive. If you need to destroy a military base or a factory, you can just use non-nuclear weapon. I think the main targets for ICBMs are densely populated cities or areas. So large countries have much higher chances to survive while overpopulated European countries, or East Asian countries can be severely destroyed.