I've heard that, but where do these viral particles come from? The mask wearer? If so, that's the goal isn't it? And if it's from outside and gets trapped in the fabric... isn't that also a win?

The arguments against wearing a mask have always been weak, the arguments for wearing a mask didn't start so strong but were well established in March/April. Anyone arguing against them after that point was either parroting stuff they heard without understanding, or was making disingenuous arguments that have contributed to a lot of misery and death for no benefit.

I don't think I heard anyone with actual medical training suggest that wearing a mask might be worse than nothing -- except for one scenario, that it might cause a false sense of security. Never once have I heard another reason from someone with actual medical training for why masks might make things worse, at least when it comes to COVID.