Obviously, if you haven't read this far, spoilers abound.
In light of the new chapter, much has been revealed. Most notably that of the viewpoint of the Invaders, who turn out to be seemingly harmless being of small stature. "Cute" is not an uncommon descriptor of their appearance. They show no obvious ability for destruction or combat ability, and unfortunately even they have little clue as to what is going on in this one sided(?) conflict.
So as not to clutter the Comments section with essays, let us keep up relevant (long) discussion here.
there are many points of contention in what the invaders say namely:
"i swore i'd give my life for the motherland"
does that mean something in a aggressive warlike manner? or are they looking frantically for something else?
"'they' aren't an enemy we can deal with! those monsters wouldn't even listen"
did they try to communicate at first? or did they try communicating after?
"why did the motherland send us here?"
were the majority of the invaders clueless about their mission? or is there some other reason/purpose that their people have in mind?
"we were set up."
are there different factions among the invaders? rifts between the motherland and the people sent to Earth?
"almost half of us went back home because of 'them'"
were there more ships in the area? after finding out the ability of the humans, why did they not all retreat?