Re: Very good skeptoid podcast recently debunking this stuff
For people like you and me, engaging with conspiracy theorists is usually pointless. Conspiracy theories have two traits:
1. Scale-bias. Big events "must" have big causes. Thus the JFK assassination has them, yet the Reagan assassination attempt in 1981 does not because it wasn't as news-worthy.
2. Self-sealing. The "you're in on it" factor. Refuting becomes reinforcing.
It's worth pointing out too that real conspiracies point to why coronavirus-is-a-hoax, or the moon landings were faked simply cannot be true. Take Snowden. The truth became known because the sheer number of people who needed to keep shtum simply wasn't sustainable. One study of real-conspiracies calculated the average quantity of conspirators and time before whistleblowers reveal it to the world. It demonstrated that if the 411,000 people who worked on the moon-landings collaborated to fake it, the story would typically have broken after 3.68 years.
John Oliver last weekend had a good thesis on how to respond. Find someone who the wacky-theorist respects and get them to nudge, not hector. Compliment the theorist's curiosity and intelligence, suggest they think critically and explore whether any credible experts agree with it. Then compliment how smart and inquisitive they are again.