edit: Think about it this way... There are dumb people on both sides of anything, it's tough to say "only their side needs to own their idiots" when lots of stupid and people run around talking absolute nonsense about climate change when it's hot out. That doesn't mean everyone that agrees with them is as dumb or even wrong at all.
If 10% of people believe it and the rest are acting - how could you tell?
Though I have charitably believed in the past they are mostly having fun with each other rather than trying to troll the rest of the world.
Have you seen Beyond the Curve, the documentary about flat-earthers trying (and failing) to prove the earth is flat? You'd need pretty strong evidence to convince me that everyone in the film was in on it.
Outlet makes a joke (for a real example “Joe Biden is refusing to leave the White House and has armed and barricaded himself.”)
Joke is spread devoid of context, still as a joke.
Trolls get a chuckle by posting it to some extremist group.
Extremist group doesn’t get the joke and adopts the narrative, fitting it into existing ideology.
Pizzagate and QAnon are great examples of this process. The other process is that schizophrenics dig up old ideas to fit their current delusions, such as “Orgone” and “Chemtrails.” Some of these ideas fit into the delusional ideation of non-mentally ill groups and it becomes a widespread conspiracy theory.
Note that this can all be very profitable, if you look at people like Glenn Beck, Alex Jones, and David Icke.