Here's a test you can do at home to see if a buff or bandana works. Put your hand 12" in front of you then blow. Note the feeling of air on your hand. Put a buff/bandana over your mouth, and repeat the experiment.
There's a reason they say "face covering" and accept those as mask substitutes. Probably not as good as a tight fitting mask of course, but definitely way more effective than nothing and not deserving of your dismissive "they don't work" unsubstantiated statement.
And FWIW, I have a mask that has a valve and when I do the same test as above, I can't feel the air. But I don't wear it because I don't like the way it fits and I don't want people like you acting like I'm somehow not playing by the rules (I don't wear buffs or bandanas either).