Hollandica, I guess it depends on the reasons? The Nazi's killed those they deamed as socially inferior or unwanted. I think some on the pro-abortion side may think the same way. Both ideas stem from a belief of what they think qualifies as human and what constitutes as "life".

Verklingen, if I understand you correctly, you're looking to the underlying moral principle with which people base their decisions regarding a specific situation or ideal. I don't think any of your examples show a conflict of interest but may show another type of conflict. Compare one type of apple to another, say killing for justice using the death penalty and killing for another reason with abortion. I believe the death penalty is just but don't beleive abortion is just. One involves a known criminal that has been tried and convicted according to the laws of the land ,the other involves the most innocent and helpless of society. The value of human life demands we protect those that are helpess but it also demands justice against those who take another life.

I don't think you can compare gun rights to abortion or infanticide. My moral view of apples can not be applied to oranges.