Remember, though, that your question is attempting to generalize a very specific scenario.
The perfect example of my complaint is World War 2. The German actually very specifically show the flaw in this statement. If we had a 1-10 scale on freedoms within countries, Nazi Germany in about late 1944 would be... maybe a 2, even for the German people. The German people would, by your interpretation, have little reason to fight a conflict.
So what did the German soldiers end up doing? Remember, Germany was fighting two fronts. On the Western front, German soldiers were actually surrendering en masse... theoretically, making a microcosm version of your calculation and determining that it was better to surrender than defend the little freedoms which existed in Germany. On the Eastern front, however, Germans who surrendered knew they would probably die even if surrendering... so from a microcosm perspective, it was more logical for German soldiers to fight as hard as humanly possible against the Soviets, knowing that the Soviets were pretty damn vengeful against the Germans.
That's my fundamental problem with this question. You're asking for people to make a stance on a question which, empirically, must be answered on a case by case basis. Unless you live in either the most or least free country in the world, there will always be someone with more freedoms than you or someone with less freedoms than you... at which point, it would be justified to protect oneself against a relative oppressor, and unjustified to protect against a liberator, all other things being equal.
Soldiers cannot possibly be expected to use this as an analysis before signing up when the country is not at war, primarily because since the possible opponent is unknown, a proper calculation cannot be made.
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