I'm going to take this as a naive question and answer it with an example. Andrew Wakefield et al published a paper based on a small number of participants. the

I'm going to take this as a naive question and answer it with an example. Andrew Wakefield et al published a paper based on a small number of participants. they effectively preyed upon desperate parents to assert that MMR caused autism. (https://pubmed.ncbi.nlm.nih.gov/9500320/ https://pubmed.ncbi.nlm.nih.gov/9500320/) When people are desperate, its very easy to get them to do stuff thats very bad for them. The problem is that in some cases that "very bad" thing might actually be quite good. For example adding chlorine to water, on the face of it, is a fucking stupid idea. However along with proper sewage/sanitation, its responsible for most of the extended lifespan we enjoy in the west. It is a grey area between doing good, through taking informed risks, and using shortcuts that require desperate people to take extra ordinary risks. For example the reason why that vaccine was a massive risk is because the immune response could have just attacked the brain tissue as well as the tumour. And as it is a learned immune response, its super hard to stop it.