https://en.wikipedia.org/wiki/Thought-terminating_cliché
As the party fielded more and more candidates who championed economic-right policies in order to attract corporate donations, the idea of “purity testing” was turned into a stock phrase to attack critics using labels, instead of justifying it on its own terms.
Phrases like “moral purity” now serve two functions: firstly, to dismiss criticisms from the Left wholesale without having to discuss them directly, and secondly, to blame them for the rise of fascism.
In theory it was also supposed to serve a third function of bullying the Left into voting Democrat, but that didn’t work.
Honestly, anyone who uses “purity test” is just letting you know that they have no standards and expect you to abandon any you have.
Yeah. Generally speaking if you’re using a positive value as a pejorative, you’re probably on the wrong side of history.
The Right did it with “political correctness”, “Woke”, “inclusion” and “equality”, and now they’re in the DNC doing it with “moral purity”.