I, for one, am rather glad that the first computers were used in warfare to defeat the Nazis, with both the British and Americans employing computers for this.

Of course, not all warfare is the second world war; in fact, most of it isn't. But I think a blanket opposition to "software used in warfare" is too simplistic. The real problems are when a country starts a war for unjust reasons, and this is a political problem, not a technological one. In many ways a sufficiently powerful military (and warfare, or the threat thereof) is vital to protect safety and basic rights.

The development of the atom bomb is how it's been used over the decades is something we can have plenty of moral questions about, but the thing is that after the development of physics up to a point, an atom bomb was kind of an obvious thing, and the same technology has also been used for many other non-warfare purposes. Technologically speaking, you can't really have one without the other (but you can make a political choice to do so).

In short, I understand why people are concerned about these kind of things, but I think solving them on a technological level is the wrong approach.