It is a nuanced issue though. There are recommendations from the World Health Organisation which say that in a community setting, for a well person “a medical mask is not required, as no evidence is available on its usefulness to protect non-sick persons“, but that a person with respiratory symptoms should wear a mask [1].

In a medical setting (or very close contact, like a few metres or so) they do help in both directions, this is standard “droplet precautions” one usually takes with a patient.

So while I agree with you that it does help in the medical setting, there is really no evidence that wearing a mask on the street protects yourself, rather than protecting others.

[1]: https://www.who.int/docs/default-source/coronaviruse/advice-...