I'm reminded of H.P. Lovecraft: that we live on a placid island of ignorance in the midst of black seas of infinity, and it was not meant that we should voyage far. There's a lot not to like about Lovecraft but I think he pegged humanity's role in the cosmic order pretty well (we wouldn't have one.)

Any species capable of reaching our planet from another galaxy will be more than advanced enough to wipe us out without effort. If there's any sort of competition for resources or territory between aggressive civilizations operating at that scale and we find ourselves in the middle, we just lose. Our "fighting" them would be akin to termites "fighting" a steamroller flattening their mound.