NdGT is Great

[abaris]

Any successful life form will be subject to population pressure and the will to survive just like us. As soon as they have the technology they will expand to fill all available niches, from one end (STS) of the galaxy to the other.

That's assuming they are also territorial apes like us. If some civilization is so much more advanced that space travel is possible, they have reached that level by not pushing the button to take themselves out of the equation. They have overcome nationalism as well as competitive religions or other ideologies. Only a united effort that isn't wasted on marking your own territory every step of the way, can hope to get that far.