If you really want to talk to these people (or better, shut them up), ask why their version of events matters. Often they are just very excited about finding “the truth” about something with no consideration of whether their version of reality will effect anything around you. If they think the Bush administration did 9/11, or if we never landed on the moon, or whatever, why does it matter?
Let’s say their internet fu is somehow better than everyone else and they found a smoking gun that says covid was an accidental lab release. So what? Are we going to kill all Chinese people? Does the virus go away? Should we not take a vaccine if the disease came from a lab? Most of their excitement is based on the belief that everything that happens has to have a grand conspiracy make it go that way. And people who believe this have probably never seen how hard it is to pull off a church bake sale. Getting people to coordinate and cooperate on simple things they believe in is already hard. Getting people to go out of their way to do secret, harmful things is rather out there.
Now sometimes the “why does this matter” helps save time in the “should I be around this person” decision, because if their delusion of why this matters involves not taking appropriate steps to protect yourself and loved ones (like taking the vaccine), they are a hazard and a disease spreading vector and you should take caution. The world has gotten relatively safer over time, to the point where people think it must always be safe. These are the people that pet wild bears. You generally don’t want to be around during the find out phase of their fucking around, unless you are making a Youtube video.
But we all know your Youtube video is fake, Ted died of Covid but they wrote “bear attack” on his death certificate because they get more money that way.