What source of information in life isn't like this? You have to trust the news, the history books, everything else. You make a fair point, but you can't simply just say the two studies can both be questioned because of the manner they are attacked.
You don't judge the the paper based on how it's being discredited. You try your best to judge the paper on it's own merits. If you lack the knowledge/information to do so, then you obviously have to live with the fact that your opinion on the matter may not necessarily reflect what is true. It's a tradeoff many of us make considering we can't be experts in everything. If it's something you truly believe in and want a better opinion on...then you have to spend time on doing research into it.
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.
You don't judge the the paper based on how it's being discredited. You try your best to judge the paper on it's own merits. If you lack the knowledge/information to do so, then you obviously have to live with the fact that your opinion on the matter may not necessarily reflect what is true. It's a tradeoff many of us make considering we can't be experts in everything. If it's something you truly believe in and want a better opinion on...then you have to spend time on doing research into it.