[downandout]

astroturfers influencing public opinion.

For the most part, people don’t look to social media to find content that helps them form their opinions; they look to it to reinforce already held opinions. It's an echo chamber.

That means astroturfing may lead to more divisiveness, as people seek out content that makes them more sure than ever that their opinion is the one and only correct one. But it does not “influence public opinion” since nobody is jumping to the other side of an issue based on astroturfing. It just makes the world a more hostile place.

[mkl]

That seems unlikely. For anything new or unfamiliar, people will not have established opinions yet. Their opinions will form under the influence of their experiences, including astroturfers on social media.

[downandout]

Sure, for something new or unfamiliar. But most astroturfing campaigns are not directed at such issues.

[moate]

Everything is new and unfamiliar to someone.

Also, pushing things further to the extremes/reinforcing the belief that "Everyone I speak to agrees with me on <topic> so I should therefor stand up for it because it's right" isn't less bad than fooling someone who hasn't yet formed their opinion.

[jacksproit]

For a lot of people it’ll be their first time being exposed to a concept.