[NoPie]

That's not accurate. Obviously there are many different studies with different conclusions. But by “evidence” we usually mean the total conclusion from all of them. In medicine it is usually done via metareviews and even then evidence can be graded to different levels and quality.

So, in short, Cochrane review shows that we don't have a good quality evidence that masks were effective. And the low quality evidence indicates that masks either had no or very little effect. Some people try to quote one or two studies out of context but that's not helpful because we need to take the totality of evidence into account.

It is possible that once we obtain high quality evidence, these conclusions will be overturned. Surprisingly there is very little interest in doing such studies.

[somewhereoutth]

Total conclusion from all of them would be a high bar, given that such a large section of society had become convinced that they do not work for reasons far removed from any facts.

Lots of people died.

[NoPie]

What do you mean by high bar? Cochrane group are specialists who do exactly that and provide gold standard of evidence. Sometimes the evidence goes against accepted wisdom. That's how science work.