"It’s tempting to treat this as a story of one flawed man and a vetting process that failed.... But the more uncomfortable lesson..."

"... is the one that the Platner boom offered before the bust. The hunger that lifted him — the overflow crowds, the volunteer armies, the sense that here, at last, was someone who meant it — was real.... Handed the chance to litigate what the party actually believes, Democrats have mostly declined.... Mr. Platner’s appeal was never really about oysters or facial hair. It was that he seemed to stand for something. He was angry on voters’ behalf about an economy that seems rigged for the powerful, and he was unafraid to say so. People responded to the promise of conviction. That signal is the one the party ought to be reading. The tragedy of a campaign like his is not only that it collapsed, as it deserved to, but that so much energy was poured into a messenger before anyone was sure of the message...."

So says the New York Times Editorial Board, in "The Democrats Can’t Go On Like This.

So "he seemed to stand for something," but we really don't know what, and instead of letting us argue publicly about what that message was and whether it is what we want, they took out the man. I think they had the ability all along to destroy him as a man, but they propped him up as a man. The Nazi tattoo was somehow okay! But when they decided they needed to replace him (presumably, because he wasn't going to win), they used the personal material to take him out.

Here's how Platner himself explained it as he bowed to the Party's demand that he drop the nomination the primary voters had given him: "I think it's really important to understand why this is happening in the timeline, why this is happening right now.... there is a reason that this is happening now...."