Don't get me wrong: I am firmly committed to the moral soundness of the principle of double effect.
That doesn't mean I'm happy about it.
The PDE is usually defined in terms of the conditions that, when met, make an act that has negative consequences morally permissible. That's really more of a heuristic, though, a description of how to reason about something. If we want to stress the fact that the PDE is a principle, we might simply say, "Sometimes it's okay to act in a way that has bad side effects, and sometimes it's not."
The "sometimes it's okay" part answers rigorists, although I suspect most rigorists either suffer from scruples or are merely contrarian. An intellectually rigorous rigorism against the PDE leads to moral paralysis, psychosis, and death. (I speculate somewhat.)
The "sometimes it's not okay" part answers laxists, which is to say most everyone most of the time, including those of us who think of the PDE as a license to act, a principle directed only against the rigorists.
But the fact that sometimes it's okay to act in a way that has bad side effects doesn't mean that, at those times, it's great or wonderful to act that way. We don't celebrate the fact that the injury to my family is outweighed by the good I do staying up till 2 a.m. instructing the ignorant and admonishing the sinner. We accept that fact, recognizing that our world is one with very few choices that have only good consequences. But we wish it weren't so, and we look forward to the day that has no evening when it will be so.
This should be especially clear in the special case of the PDE that we call "remote material cooperation with evil." The very expression contains the term "cooperation with evil." That should clue us in to the fact that we aren't talking about something that is altogether nifty.
But don't we often think it is altogether nifty? Once we satisfy ourselves of the moral liceity of a particular instance of remote material cooperation with evil, aren't we often wholly satisfied with ourselves, with no thought of the evil we are cooperating with troubling our minds further?
The PDE may justify our remote material cooperation with evil. It doesn't justify our satisfaction.