I'd say your step dad was "fighting" in the Vietnam war, he just (presumably based on your post) didn't see active combat. But it depends what you define as "fighting." I think the average person in the US understands fighting in a war to mean being part of the military at the time of a war and supporting the war effort, but would have varying views on the extent to which that support must be directly or indirectly linked to live combat. In this case, I view your step dad as having been directly supporting the war effort and his proximity, even a hundred miles away, made him a potential candidate for live combat if needed. For example, the ship could fight in the war without those on board ever stepping foot on land. In some cases there could be value in measuring the level of fighting a person was engaged in, such as to predict potential needs to provide post war services like counseling for PTSD, but your step dad was fighting by provide whatever auxiliary services that ship was needed for and placing himself at risk for live comba

What do you mean nothing horrible happened before 1941? Jews were targeted and oppressed for the decade prior with their rights being limited and with instances of violence. That's not "the Holocaust" but you said nothing "horrible" happened then, and that was indeed horrible.

Second, why would a baby not count as a survivor in your example? Nazis didn't exempt killing Jewish babies during the Holocaust, so for example if a Jewish family during that time was in hiding and had a baby, then that baby is a survivor the same as the rest of the family. Had the family been discovered in that hypothetical, they'd all have been treated similarly, and in fact the baby would be more likely to be executed quickly since they can't be exploited for labor.

Finally, your last sentence appears to define a Holocaust survivor as someone "who was a prisoner of war," which doesn't make sense. I'm assuming you made a mistake. But to be clear, almost none of the Jews sent to be executed were there because they were a prisoner of war, and they weren't soldiers. A few did fight but most of the Jews were noncombative civilians.

I agree with the general point that not ever Jewish person who lived during world war II is per se a Holocaust survivor. I don't think anyone in this thread is arguing that though. But an individual may be a survivor without having gone to a concentration camp. Evading Nazi detection and the camps is also surviving.