A bad mask (eg a bandanna) means less virus gets out, but it is more likely to get out in the form of a fine aerosol that hangs in the air for hours. On the opposite end it is a reminder not to touch your face (prevents transmission from your hands) but won't stop you from breathing in an aerosol.
Likely still a net win, but kinda a hard thing to do good research on.
There is no doubt that masks that are designed to block things the size of viruses help. Just issues about who is the highest priority to get them when they are in short supply.
Who is debating this? I haven't seen a reliable "con" side of this debate, they are all weird "people will take less care", "cloth masks are not as good as N95", "people will wear them poorly and the mask won't be as effective".
These are all "perfect is the enemy of good" fallacies, not "debate".
Also, how does a bad mask increase aerosol? That makes no sense.
I can't find the source on which I based my aerosol comment on, but the idea was that a large droplet which would have fallen gets trapped by the cloth. When it gets through, it comes out as a fine mist.
Given that I can't find it repeated, I suspect that it may be misinformation on my part.
I can't find the source I saw it in, but the idea is this. If you cough, large droplets coat the inside of the cloth, and then are forced through the weave of the cloth and come out as small droplets. The smaller the droplet, the better it hangs out in the air.
