Nobody thinks anyone has pure intentions. Nobody even agrees on what “pure intentions” are. The question is whether it is a viable strategy for regime change going forward and whether it is worth the cost. Or if regime change would even bring in a better regime, rather than anarchy or a more-extreme version of what was already there. Civilians are often the majority of the people dying or injured during any larger conflict. Up to 90% of the casualties, if the war is fought in heavily populated areas. This is not the sole determining factor in whether the war is unjust or unwise. Many more German civilians died during WWII than soldiers did. That doesn't mean the Allied invasion of Germany was a bad idea.