No, the problem is that AI takes an existing problem and makes it massively worse. Because there is basically no limit to the amount of plausible-sounding drivel that AIs can spew, they can drown out all other voices in a way that regular shills and propagandists couldn't. Even organized rings couldn't produce the same volume that AIs can.
Sure, the internet had, say 20% noise back before spam, shills, and propaganda took over. Now it has 50% noise, maybe even 80%. It's still (barely) usable. But what happens when the noise is 99% of the content? 99.9? That's not "making it slightly worse", that's a phase change that makes it completely unusable.
It never had to sound plausible. AI didn't cause MAGA to believe Haitian's were eating people's pets. AI didn't cause them to believe that schools were buying kitty litter for furries. It's a population who has been conditioned over decades to believe the most wild shit as long as it comes from one of their "trusted sources" and anything that is counter to that is the "liberal media". Fox News et al are far more damaging to our society than generative AI is.
I think their use of the word “plausible” was in reference to a comparison to content generation in the pre-LLM era, which was limited to GANs and Markov chains.
Sure, the internet had, say 20% noise back before spam, shills, and propaganda took over. Now it has 50% noise, maybe even 80%. It's still (barely) usable. But what happens when the noise is 99% of the content? 99.9? That's not "making it slightly worse", that's a phase change that makes it completely unusable.