there are some people on social media whose claim to fame is replying to every tweet that a famous person makes
if someone has a million twitter followers, and you reply to every tweet they make (assuming they don't block you), it's trivial to get 10k+ followers with no real effort, even when you're a nobody, just as long as you parrot opinions that are popular by people who follow the more popular person's account (though some people hatefollow instead of following people they like)
this reminds me of those kinds of fish that cling to bigger fish, like how sharks have little feeder fishes stuck to them