Zarquon-
With all due respect, you are the one that is being illogical. You are taking my proposition that a summary execution may be morally justified in a particular instance, and drawing the conclusion that summary executions must therefore be must be justified in a wide range of instances. That does not necessarily follow.
To the contrary, to be consistent, I need only admit that summary executions might be justified in comparable situations. And I think I can admit that.
For example, if you (extremely) hypothetically transplanted Dachau to Alabama and substituted blacks for Jews, and KKK members for SS men, I would have a hard time seeing the injustice in a camp liberator shooting any hooded,white-robed individuals they happened to find on site.
PS -- Kant's moral philosophy is banal. It took him page after turgid page to come up with the conclusion that we should live by the Golden Rule. Duh. His metaphysics, on the other hand, make him worthwhile.