'lets build this McGuffin thing that we conveniently found at our doorstep at the very right moment and which we aren't even sure how it would work, but we will use resources of the whole galaxy to build it' story was hardly any better.
In the movie Contact the Earth wasn't under a genocidal attack by a overwhelming forces of a highly advanced alien race, they just received some blueprints that they thought should do something. And It was at least known how to activate the thing. With Crucible, they didn't even know until the very end.