In general, I believe all the careless killing is based on a conscious, semisecret foreign policy based on (among others) these two principles
1 Fulfilling a perceived need to fully develop the drone program and work all the bugs out, to prepare for "the Big One", [WW3], and
2 Securing the U.S.'s energy future for the rest of this century and into the 22nd century. In this view, killing of innocents is unfortunate but necessary. The people of the countries the U.S. attacks are considered less than fully human*, are considered expendable, and in any case are seen as a renewable resource, unlike the oil and minerals above which they live.
*There is lots of evidence to back this up; but one word says it all: haji
In even more general:
In my daily life over the past few years, for every person who cares about the war, or about the drone part of it, or about the root event 15 years ago, there are fifty people who are either uninterested or hostile if the subject of U.S. wars is brought up.
I'm very glad that some people do care, even to the point of some sacrifice; these are heroes in my book (the author, among others). But so few! It really seems to me that the vast majority of Americans rarely even think about the ongoing war, nor do they factor the war into their voting choices (at least, so it seems)- except rarely.
The drone war: "Out of sight, out of mind."
I suppose this state of things was/is part of the overall "volunteer" military plan.