To understand it, you need to know recent American history. During the unpopular American intervention in the Vietnamese civil war, draftees and volunteers returning home from duty were met with protesters, who showed them exactly as much respect as you might expect that an anti-war protester would offer to a soldier.
The canonical anecdote is that the returning soldier was spat upon and accused of killing babies. I have never actually known any Vietnam veteran who claimed to have experienced this, nor any former protester who admitted to doing it.
Nevertheless, the military leadership decided that this should not be happening. And so the Pentagon started dedicating more of their budget to the manipulation of public opinion. They have essentially produced the current state of public opinion through four continuous decades of advertising.
It is occasionally revealed that the "thank you for your service" portion of a sporting event is sponsored directly by a hefty cash payment from the military.
You can see how the federal government actually feels about its veterans by how it treats those no longer able to turn their assigned cog in the war machine. Not only are disability claims routinely reduced or denied outright, but the medical care that veterans get is often far inferior to that available in the nearby non-VA facilities. The vets find that for all the cheerleaders they see shaking pompoms on the sidelines while they are in the game, they are still completely alone with a traumatic brain injury after time runs out and everyone goes home.
Part of me wishes it really was like _Starship Troopers_ (the book), and that veteran amputees would hang out near recruiting centers without their prostheses visible, talking loudly about all their VA, disability, and pension problems.