I think there's sufficient evidence that it's a good idea. You can't go by the WHO; they only recently concluded Covid-19 might be an airborne virus.
As the Mayo Clinic advises, even ordinary non-surgical cloth masks will trap some droplets on the part of both the giver and receiver potentially reducing viral loads in those who come in contact.
The viral load theory is not proven with repect to Covid-19, however immune response to viral infections in general adheres to that theory--the fewer and smaller the viral particles the immune system has to fight off the better job it will do. You can wait around to get some definitive study demonstrating that Covid-19 does or does not adhere to this theory but you'll be waiting a long time. It would be unethical to run a controlled test. If the viral load theory did not hold that would be rather unique in the behavior of immune response so reasonable precautions are in order.
It's a risk/reward proposition. What's the risk in wearing a mask when in public? An inconvience? A minor discomfort? Steamed up glasses at times? Some folks with breathing difficulties might have have an issue with it and should consider other precautions being in an at-risk category to begin with. The reward is that the viral theory holds which has a good chance of being true.
One thing we do know epidemiologically speaking: places with lax or non-existant regulations spike; those with mask wearing and distancing protocols in varying degrees up through shut downs and lockdowns show declining incidence.
Every attempt to downplay the severity of this pandemic has had to be walked back. Now we're down to parsing whether the positive affects are limited to distancing while an unproven but compelling theory is ignored?
"My American freedoms" is a ludicrous excuse for not wearing a mask. There are a million ways in which law and regulation controls one's life in untold numbers of ways one never thinks about and which are largely to one's benefit. The world and the law may also have injustices which are duly protested or taken to court. Having to wear a mask, which nobody likes, doesn't rise to the level of any meaningful protest. It's a shallow symbol of independence.