Have you read any of these studies? I've read loads of them, and none of them match the claims made for them - they are pretty much all meta-analyses of studies in medical settings, and they then make the jump to conclude that they work among the general public, with no evidence for that leap and presumably hoping that nobody will notice that they are comparing apples with oranges.
I am not aware of a single case where mandating masks (which a number of countries have done at various times over the past six months) has shown any measurable reduction in transmission.
The onset of 'meta analysis' has been one of the more nebulous aspects of 'the science' being used to justify all these arbitrary restrictions. In most cases it seems about as scientific as me writing a blog post, but there you go. A common theme seems to be something like the below:
1) Prof J. Bloggs writes a meta analysis of a bunch of studies of varying (usually very low) quality dating back fifty years or so (where in the fine print they discount the ones they don't like) and submits it as a 'pre-print' or even worse as 'analysis' (aka an opinion piece) with 'informal' peer review to a journal, and shares it on Twitter, perhaps with some recommendations that X needs to be banned or mandated;
2) J. Smith with tens of thousands of Twitter followers finds this and announces new science on X restriction and its effectiveness, maybe or maybe not referring it to as an opinion piece;
3) J. Doe of the BBC or other newspaper writes an article about how new watertight science proves beyond doubt that doing X is leading to countless deaths
4) M. Hancock or N. Sturgeon announces an immediate ban on X and related activity Y to save lives and protect the NHS, by which time Prof Blogg's colleague has released a another half a dozen meta analysis on different topics, cycle repeats (with occasionally somebody looking back at the first one and finding out it was bollocks and never went beyond pre-print analysis).
