These aren't like a single real person pretending to be Americans because of their deep interst in American politics.

These are paid astroturfers probably more like call centers, paid for presumably by all sorts of interests from foreign intelligence services, to businesses (or select executives), to internal political groups or politicians trying to manipulate public opinion.

Both political extremes are suffering from this kind of manipulation where real concerns are twisted and amplified for lets say the more gullible half of the population (gullibility knows know political alignment exclusively). The excluded middle is afraid of the people who have been manipulated this way (death threats also know no political boundaries).