Cleaning up the rest wasn't difficult.
After all, once they witnessed how their Generals died, their morale pretty much took a solid hit and they collapsed entirely. On the other hand, humans were even more energized after the deed so killing the rest didn't turn into a huge problem.
Sufficed to say, Humanity won this clash. They proved that they could survive the relentless assault of the invaders and could continue to flourish.
This victory was celebrated by everybody, but underneath the celebratory mood, many people knew that this isn't the end. If anything, the real battle just started.
But that's a matter for later. Right now, they should just feel relieved that they didn't suffer much damage.
There were casualties on their side too. Some people died even with Ashton's blessings. It is disheartening but this is an expected outcome, after all, the invaders are strong, and that much is proven from what everybody saw in the broadcast.