I’m afraid research indicates you are incorrect. There is a benefit to a mask, any mask over no mask.
See below summary of a published (and therefore peer reviewed) paper.
Testing the efficacy of homemade masks: would they protect in an influenza pandemic?
Anna Davies, Katy-Anne Thompson, Karthika Giri, George Kafatos, Jimmy Walker, Allan Bennett
Disaster medicine and public health preparedness 7 (4), 413-418, 2013
Objective
This study examined homemade masks as an alternative to commercial face masks.
Methods
Several household materials were evaluated for the capacity to block bacterial and viral aerosols. Twenty-one healthy volunteers made their own face masks from cotton t-shirts. The number of microorganisms isolated from coughs of healthy volunteers wearing their homemade mask, a surgical mask, or no mask was compared using several air-sampling techniques.
Results
The median-fit factor of the homemade masks was one-half that of the surgical masks.
Both masks significantly reduced the number of microorganisms expelled by volunteers
although the surgical mask was 3 times more effective in blocking transmission than the homemade mask.
Conclusion
Our findings suggest that a homemade mask should only be considered as a last resort to prevent droplet transmission from infected individuals, but it would be better than no protection.