Some conspiracy theories have merit; it's possible that there was more to the assassination of JFK, that's an idea that I wouldn't discount at all. I also didn't entirely debunk my uncle when he suggested a conspiracy behind 9/11 because he had worked for the UN for many years, so wasn't just 'someone on Twitter'.
Re Princess Di, I didn't dismiss it. I read up on it and concluded that it was highly unlikely, mainly because she would very likely have survived if she had just been wearing a seatbelt. (I didn't suspect the Royal Family, as they would surely have been better prepared for it if they had contrived it themselves. But I did wonder whether it might have had a connection with her landmine campaign.)
I'm a SA survivor, and my F was part of a paedophile network, so I certainly wouldn't dismiss suggestions about sexual abusers in high places. There's also a lot of corruption involved with sex trafficking.
Re the moon landings, I don't believe there's any basis for thinking there was a conspiracy involved. If there were, surely the Russians would have encouraged this theory? Plus what's the explanation in that case for what happened with Apollo 13, a mission that didn't succeed, and when the astronauts very nearly didn't succeed in getting back from space safely?
Other conspiracy theories are completely ridiculous, for example Flat Earth exponents or those now suggesting COVID-19 doesn't exist.
It's not a case of either/or for goodness sake, it's a case of weighing up the evidence and deciding whether a conspiracy is likely or not.