But here's the thing: If you scroll down the list of institutions above, you'll notice that Trump has gone toe-to-toe with basically every one of them — or, at the very least, he's questioned something they hold sacred.
And really, why should the military be any different?
The presidency? Trump has questioned the legitimacy of both the 2012 and the 2016 elections (yes, already), and he spent a good portion of the years prior suggesting President Obama wasn't a legitimate president.
The medical system? He called one of the most well-regarded doctors in the world, Ben Carson, just an "okay doctor," and his personal medical evaluation included his doctor's unscientific claim that Trump would "be the healthiest individual ever elected to the presidency."
The media? Besides his general disregard for us nasty people, he has also blacklisted us from covering his events, suggested he might ease libel laws as president to make it easier to sue media companies, and even mused about killing journalists (while opting against it).
To be clear, not all of these things are on the same level, but there is a common thread running through all of them: a general disregard for the established institutions of American society — and a willingness to question the things they hold dear.
If you're a doctor, you might blanch at Trump's dismissal of Carson's credentials and his hyperbolic medical review, just as if you're a Catholic you might be turned off by him questioning God's messenger on Earth. It suggests he doesn't respect your institution and its underpinnings.
But if you look at the chart above again, Trump's strategy — assuming he has one — begins to make some more sense. That's because very few of these institutions are held in high regard, and it's only getting worse. Basically every American institution is losing public confidence right now. Only two garner a "great deal" of confidence from more than a quarter of Americans.
This is the kind of environment in which a burn-it-all-down candidate can succeed. And Trump is, if nothing else, a burn-it-all-down candidate.
The problem with holding nothing sacred, though, is that you hold nothing sacred. And eventually you risk alienating people who do hold something sacred. That something, for a lot of people, is the military — hence the increasing cavalcade of Republicans saying they'll support Hillary Clinton and the decision by even Trump's top allies to distance themselves from his criticism of the Khans.
Will this be Trump's undoing? Far be it from us to predict that. Many thought his first sacrilegious comment about the military — the McCain one — was the beginning of the end. There was no way he was going to recover from that.
And yet he did. Trump's anti-establishment campaign was what Republican primary voters were looking for. He attacked plenty of institutions and people but didn't alienate the biggest constituencies — evangelical Christians and white men, in particular.
Of course, in the process, Trump managed to alienate much of the rest of America. Recent polls show 60 to 65 percent of the American population doesn't like him. His comments about women have made him historically unpopular among them. Same with Latinos. So the indiscriminate feuding can't be considered a complete success.
The conceit of Trump's entire campaign has been that which worked before will work again and that Trump will win by sheer force of personality. The smart people were wrong before — beginning with the McCain stuff — so why would they be right now? Trump will prove them wrong.
So he'll keep doing this. He'll wager that people's fear of radical Islamists will override their reservations about a U.S. presidential candidate criticizing the parents of a fallen soldier — just as he wagered that anti-establishment Republicans didn't like McCain enough to think Trump's criticism of his war service went too far.
And maybe it'll work. But it's also worth noting that Trump's decision to go after the parents of a fallen soldier is completely in keeping with his entire campaign. Perhaps he went too far this time. But it's completely unsurprising he went there.