While your post is somewhat true, the media and politicians are claiming that wearing a mask will prevent the spread of the virus, which is a lie
By decreasing the amount of large droplet spread, it does help reduce the spread of the virus. The extent of “help” provided with regard to the spread is perhaps enigmatic, but there is certainly a difference. Some studies have shown 10-20% decrease in transmission of Flu vs. no mask regarding people in close proximity to those infected (e.g. caregivers or family members).
If anyone says it flat out prevents it, they are lying. If someone claims that it can help prevent the spread of it, they are speaking the truth. The discussion / definition needs to be parsed like that and people need to understand wearing a mask - any mask, is not a panacea.
There also remains a large contingent of people who may have enough T-cells from previous cold/flu infections which help them to fight off covid-19 or any viral infection of a similar nature (corona viruses in general). This can also skew the stats of any study looking into this, which is why I state that it is enigmatic.