This post is based on major spoilers from the show, so if one does not desire to be spoiled, skip this post.
The skitters are the enemy. Plain and simple. They destroyed the basis for human culture, and decimated our ranks. They enslaved the children, and wiped out all others. It’s hard to say that these creatures have any of what we would call “humanity” or “mercy”. But as we watch, the show reveals a much more layered enemy, which has problems, conflicts, and values. It turns out that the Skitters are harnessed creatures, created via the harnesses which contaminate the children, and allow them to be used as pawns and weapons. This includes Ben and Rick, who seem to have recovered to a certain degree, but are still affected by the genetic traits of the Skitters. They can trace the radio signals that we assume are used by Skitters to communicate. This gives them unique value for the 2nd Massachusetts.
Here is what is important about the Skitters. Their desire (Or the one placed within them by the currently unnamed third species) is to either A) harness kids, and b) kill adults. The constant of these two of these elements is either the destruction or theft of the victim’s “humanity”. This removal of humanity is the worst threat they can do. Skitters, we are told, “Do not want us there”. They desire the destruction of the very thing that resists them; the human spirit. Humanity has no desire to just back down. And that is what makes this show brilliant. It plays the human spirit against the enslaving race who wants nothing else but to destroy and remove the human race’s spirit permanently.