And fortunately, it's easy to understand the mechanism of action that explains the positive impact of masks: the primary means of covid spread is virus conveye

And fortunately, it's easy to understand the mechanism of action that explains the positive impact of masks: the primary means of covid spread is virus conveyed not individually but in large water droplets. Any filter that impedes the flow of these droplets is very likely to diminish the spread of the contagion. Therefore, anyone who is physically within the field of oral spray of an infected person should benefit from BOTH parties wearing masks. If all scientific explanations also came with strong and plausible proposals of causation, science-based advice would be much harder to dismiss, whether that dismissal is motivated by mechanism-free (and evidence-free) theories like tribalism or not.