“Or would you just blow up their atmosphere into outer space sending their planet’s evolution back 3 billion years?”
They can’t, they are stuck here and coexist with us. To destroy us is to also destroy themselves too.
And that is why they are worried about us blowing ourselves up. It will destroy them too.
Not talking about any ‘stuck aliens’. I’m talking about advanced civilizations that don’t want us FTL-travelling in space bringing politicians, corruption, greed, bad habits and nuclear weapons to them. They’d strike first to prevent that.