[James]

Anyway, these far-out theories often end-up being used as straw-man arguments in favour of the original target of the theory.

There's (relatively small) groups on the Internet that buy into the conspiracy (and reinforce the impression to each other it is true), but the general public treat them as nonsense. Then supporters on the other side can use it as a straw-man.

The example I can think of recently is the 5G conspiracy with regard to Covid vaccines.