It doesn't have to be everyone verifying everyone - just that a reproducible result tends to be more trustworthy. This is why reproducing results from other studies are also valuable scientific endeavours.

But you know, just verifying that it is reproducible takes time. Ideally you would have a system that enable you to trust everything you read with minimal work. Like if I claim the world is round you would know from my awesome reputation / fancy title / little green WoT indicator, that you can take that at face value.

In this case the poster tried to use fancy title, but found that it didn't work satisfactorily.

> The weight of people -- supposedly credible scientists -- that they were able to bring to bear to speak against him calls into question effectively every controversial scientific finding.