I guess that's an aspect of conspiracy thinking and brainwashing - the more vague the threat, the less you have to justify.

"If Trump wins, he's going to ruin America!"
"How?"
"Just... You know, like he was doing before!"

"Once the Jews control everything, we're done for!"
"Why?"
"Because... They... They like to own everything!"

"If they put up those 5G towers, they'll give us all cancer!"
"How would that help?"
"Well, once we all have cancer... It'll... Kill us all?"

The less specific the outcome, the less you have to detail your fear and think about the process and the end result, which always makes the fear itself start to feel less real when you start to see how many moving parts there are to it.