Lemmy is a poor choice for astroturfing, not because of small user count but because no one here is going to hesitate from removing their content or banning them from the site. On regular social media you can act like a shill and get downvoted and hated on, but here the punishments are actually handed out, and even if their home instance doesn't ban them others likely will, effectively crippling said campaign.

These campaigns work on social media services that will protect them due to corporate interest, something that basically doesn't happen here.