So Here's why they wouldn't attack us...

To generate and store enough energy to "cross" the cosmos, even to the nearest M-Class..
We can assume Alien-dudes are Completely set in terms of natural resources..
They wouldn't bother coming to our planet, because the only resource unique to earth is possibly the mildly-sentient humans, and we are very bad for labor vs ROBOTS, which the aliens could power with their near-unlimited Energy..
And because these aliens are smarter than us, based on their technological premise, they sure as hell wouldn't want dum-dum humans for brain work..
We already know that the "natural resources" as we know it "the elements" are in abundance in the universe..
And if the Aliens had the Energy prowess, they could just make whatever they need @ home much more efficiently, without having to come to earth and violently take it from us and then ship it all the way back to their planet..
Here's an analogy.. (Rewritten for clarity)
The aliens are Wealthy Adults living in Maine
The earthlings are children with icecream cones living in California
Why would the Wealthy Adult drive all the way to California just to take icecream cones from us earthlings..
The cost of the trip GREATLY exceed the resources necessary to purchase or even PRODUCE the icecream at home.