Want to see if a certain mask, or if any mask is effective? Take a hit off of your cigarette, joint, cigar, or whatever. Exhale and notice how far the smoke goes. Take another hit and quickly put mask on. Exhale and see how far the smoke goes.
It’s not a filter, it simply slows and disperses the stream so that your germs don’t go so far. That’s all.
It’s simplistic and not 100% accurate, but so are many of the people arguing.
I have a cloth one I have to wear at work. It’s easier if you imagine that it’s Taylor Swifts underwear.