I think @Forever_Free is spot on.
They would do anything just to avoid having to admit to being wrong.
I had a discussion with someone who thought Covid was a bioweapon by China. I asked them what the purpose of the weapon was, and they said it was to sell medical supplies. I said that if it was true then it was a stupid plan because the world is now full of countries producing vaccines and China can’t even compete. They then changed to China doing that to invade other countries. I said that it would still be a stupid plan because it’s been 2 years and China hasn’t got any country under control yet, and besides China themselves are being worked over by the virus. They then said that that was because China wanted to murder people with different political ideology. I said that it was still a stupid plan because the entire country is now affected and not just some “targeted” individuals, and besides if they really wanted to off specific people, they would never make their method known, but as we all can see the virus is recognized by everyone in the world. They then said maybe China just didn’t think the virus would spread like that.
There is really no winning. I believe anti-vaxxers has the same mentality.
We even has a user on here now gone making a thread saying that we should all abandon vaccine altogether and focus on develop a way to time travel. His reasoning is that the vaccine is a lie, no one is immune to the virus, and the (US) government is corrupted and didn’t respond well to the pandemic.