D13 was the one that instigated the rebellion, kind of like D12 at the end of Catching Fire.
So nuking D1, for example, wouldn't serve any real purpose. Also D13 was a huge threat, so there's that.
True, but nuking seems like a waste of the resources. They couldn't just send in the death mist? Or drop bombs filled with Tracker Jackers? Damn it, President Snow, why don't you ever think anything through. Then again, he wasn't in charge during that point, so I guess it's not entirely on him.
Where do you suppose Mockingjay Part 1 will end?