So what? We know that well fitted masks are able to filter virus particles, we don't have to do a randomized controlled study on school children to prove it.

It's weird that people arguing against masking as a policy intervention go after the masks rather than the obvious problem, which is compliance. When someone tells you that you have to have a mask on to be in a building and then pulls their mask under their nose (happened to me last week), the effectiveness of masking isn't being evaluated, it's the effectiveness of masking as a policy intervention that is being evaluated.