In general, masks are something that the sick person wears to prevent germ spread. Same idea as why surgeons wear them in the operating theater.
The only kind of mask that's going to filter particulate matter out of the air (i.e., be effective against the virus for someone who is not infected) is something that has an airtight seal.
Yes, so you agree, masks hinder transmission by, in your understanding as presented, decreasing the ability of sick people to infect healthy people. That is, masks reduce transmission.
Have you seen any of them cite a research paper showing that? I haven't, I'm open to suggestions if anyone has one.
Same thing with the "keeping schools open won't spread the virus" thing in the UK; lots of establishment scientists saying "trust us" but a dearth of papers detailing how the established beliefs are wrong that schools are prime transmission vectors for ARI (and closing them has helped to hinder influenza trasmissions in the past).
Not being snarky; if you've got backing for "masks don't hinder viral spread" then lets see it.