The way I see it it's the scale and access. You can spin up an AI bot and make anything trending without a need to pay for a bot farm. And with how most media sucks at verifing sources it will be reported as truth.
They add human sounding language generation. You look at it as whole, I'm seeing it as a piece of the puzzle that combined will make the issue from an annoying inconvenience to a real problem.
I guess you're right, every little helps to make things worse. But as I said the mainstream news sources aren't trustworthy anyways. The media is already ruined behind repair as a source of truth or even valid information.