I think we are socialized to not care about insects the way we care about other people, and even animals. Insects are "gross" and "ugly" and (legitimately) scary sometimes. They can also startle us. That being said, I do feel guilty for killing insects, but it is something I still do sometimes, if they are in my house. I guess I don't have it all figured out, but I do apologize to them and sometimes send a prayer.