A friend recently observed that he had more in common with people in his opposite political tribe than he did with ostensible centerists, and he said it was because the people on the other team also believed something, where the ones in the middle were in-effect, nihilists, or believing nothing. I mention it because when I thought of nihilisim, I always interpreted it as an active kind of anti-belief, or against all belief, instead of a bland passivity, detached from a moral anchor or foundation. For this kind of nihilist, the thought-terminating cliché is the necessary boundary of their ontology about the world. It's the person saying, "it is what it is," as they do horrible things. If you have ever spent time in bureaucracies, it is easy to see how a bunch of people trained to accept small injustices passively can be mobilized into an atrocity machine. They're "de-moralized," which we misuse to describe frustrated efforts, when what it means is that by lacking roots to beliefs and replacing them with this thought-termination, they do not exercise moral agency. They're just following orders.
I've concluded the clichés are worse than thought terminating, they are jingoistic slogans of nihilism people repeat to justify and release themselves from moral agency. All this is to say, it's an important concept. Thought-terminating clichés are the mental reference points for the origins of what we understand now as the banality of evil.