but when the majority of those americans don't follow or care about politics or news, well placed comments and news stories can have an outsized effect. also, sadly, its hard (and unprofitable) not to look at idiots yelling.
I find it doubtful that those trolls are limited to a single account each.
Back in my voat days there was an individual who ran 7 different accounts. They all posted the same far right cherry picked news stories about immigration and the evils of Democrats. But would constantly change accounts. So in a short period of say 2 hours they would submit 3 dozen news stories artificially inflating an issue.
Between the mass posting and commenting either a quote from the article or some circlejerk comment, they quickly surpassed 100k upvotes on nearly all accounts and gave the impression of a valid, real person.
This is just one example, but with the anonymity online, its easy to create a facade of public opinion.
Simple math here... There are at least 200M Americans online. How many trolls do they have? Say that they pay salary for 10k Russians who can speak English at a native level and fit in online. That is a drop in the bucket compared to the native population. If you ignore those yelling from the extremes this is a total non issue.