It's been less than six months since Germany's armed forces were largely filled with kids who spent two months training and four months sleeping in barracks. Military service in most nations, Germany included, is a lot like jury duty mixed with high school. You serve a short period of time because they'd really rather have you young and you're raw cannon fodder to dissuade your enemies from thinking you have no standing military. And in most of the first world, there's no real "enemy" either. The only reason Germany even has a military was so that NATO could buttress the Western Europe theater of operations against the Soviets. There is no existential threat Germany will ever face in which a standing army will be useful. Professional soldiers, then, are essentially mercenaries - they want to make a living finding people to kill. And, as #b_b points out, Germany has a shitty history of dealing with "existential threats" in any event. "Germany" as a country isn't even as old as the American Civil War... and wasn't anything more than "Prussia XL" until after WWI. Nonetheless, in that brutishly short period of time an expansionist "Germany" brought the Western world to ruinous, unlimited total war not once, but twice - and completely destroyed itself in the process. Whereas Spain, France, England, Portugal, Italy and Scandinavia have "country-like" Royal traditions going back hundreds and hundreds and hundreds of years, Germany spent two millenia as warring tribes and scattered duchies. We have a different relationship with war and soldiers because the United States is an excruciatingly war-like country. We haven't faced an existential threat since the War of 1812 but have fought wars of conquest and wars of expansion every generation like clockwork. Not only that, but we never "lost" until Vietnam - and the revisionist history on that conflict was we "lost" because "our boys" weren't allowed to play by the right rules. The United States regards its military campaigns the way the British regarded their Navy - we kill everyone everywhere all the time because that way they never can threaten us. Soldiers, then, are like cops - they just do their thing further away. Whether or not this is a moral way to think about it is another discussion entirely, but the fact remains that "a kid on jury duty" is a very different social construct than "he who mans the wall and keeps the darkness at bay."
RE: treatment of soldiers. I've always been uncomfortable with the unconditionally glowing praise we give them. The attitude our country takes towards soldiers takes for granted the fact that morality is not black and white. Sometimes our soldiers do bad things, but we always downplay that like it's a non-issue. I'm not saying that we should assume that every soldier is guilty; I'm saying that we shouldn't assume anything. Doctors and scientists have a direct, positive effect on our daily lives, but we don't automatically assume that all of them are imperfect and worthy of praise -- nor should we.
So, if a soldier is returning or going to active duty and is allowed to board my plane before I do, I'm okay with that. If the people on the plane applaud their choice to defend us, I'm okay with that too. I honestly don't know anyone that thinks that just because someone is a soldier, they get a moral pass though. Wrong is wrong but service is service too.
I do too -- but I certainly think that our cultural attitude toward soldiers is above and beyond just appreciation. We appreciate a good teacher. We appreciate a Thanksgiving meal. What we show for soldiers is more akin to adulation and applause.