The best stories don't over-explain. They allow the reader's imagination to fill in the missing pieces.
It's effective because other terms have been thrown around so much that they've lost meaning. Racist. Fascist. Nazi. Sexist. Hypocrite. These accusations have lost all meaning.
But "weird" makes you sit back and think about it. And your mind fills in the blank. Yeah, now that I think about it, that person is pretty weird, about xxxx issue. You and I might not even be thinking about the same thing, but we both figured out something that's offputting and weird about the candidates. Why does Vance even think about these things? That's pretty weird.
And because our mind filled in the blank, it's an idea that sticks. But there's nothing concrete for Trump and Vance to respond to, because they might respond to something that we haven't even thought of yet, that also happens to be weird. The more they push back, the weirder they become.
I think it's brilliant.