I don't need to hear that again

You'd think you could win an argument by showing that you're right and that the other person is wrong. But you'd be wrong:

How do you opposed a cause you regard as dubious without unwittingly legitimating it? For instance, remember when one of the many justifications offered for the Iraq War was that Saddam Hussein was in cahoots with Osama bin Laden? Even though that idea was patently false, efforts to debunk it actually reinforced the connection between Hussein and Bin Laden simply by featuring their names in close proximity.

It seems that the public relations industry is to blame for diverting the energy of people who actually take the time to make reasoned arguments into an endless game of Whac-A-Mole with zombie ideas that keep popping back up, long after they should have been decently buried:

The best public relations operations involve repetition and media attention that you build on progressively. The more your name is seen, the more it is remembered.

Ignore terrible ideas and you surrender the floor to your opponents. If you try to demolish them, you feed your opponents the oxygen of publicity. Catch-22. 

I don't have a solution, although the next time you hear somebody using dumb repetition to enhance awareness of their particular brand of bullshit, maybe it would be better to treat them as you'd treat a persistent bore in everyday life:

"(Name). are you aware of how often you repeat yourself?"

"You've told me that before."

"Do you feel I'm hearing you well enough?"

"What do you need from me now?"

"When you need to repeat yourself, I feel _________ (and I start tuning you out)."

"That's the third time you've told me that."

"(Name), I don't need to hear that again."

"From now on, when you repeat yourself, I'm going to call you on it (or put my fingers in my ears.)"

"I'm going to hold up a finger for each time you repeat yourself."

"Stop."

"If you're not sure I'm hearing you, ask me for a hearing check, OK?"

From Response Options to a Repetitive Person - Peter K Gerlach

Because trying to win an argument by endlessly repeating the same point is a disorder, no matter how many public relations professionals try to normalise this sort of thing.