You think that pulverizing many kilograms of plutonium in the atmosphere is "no problem"?

You also completely ignored the arguments we already placed against you: The gravity tractor would not, I repeat, not have only a "single shot". There would be many years to build and launch any number of them.

Furhtermore, a ballistic missile can not even reach orbit - they're called "ballistic" for a reason, being that they fall back down. They most definitely can not reach escape velocity. You need pretty much the exact same equipment to get a nuke out to an asteroid as you need to get the gravity tractor there.