So the DANMASK study did look at Sars-Cov-2.
They studied whether mask wearers V. non-mask wearers were more likely to catch Covid - the difference they found was 1.9% compared to 2.1% (non maskers). I think it has been acknowledged all along that masks provide no protection to the wearer (unless FFP3.)
It is true that they didn't set out to study whether mask wearers protected others, and that is stated in the piece i.e. source control.
So yes that study does not comment on effects on transmission - absence of evidence just means it hasn't been studied and further RCT's - and RCT's in the community not healthcare settings - are needed.
Worth bearing in mind that this is one of very very few RCT's on the subject and most other studies involve observational qualitative evidence, plus computer type modelling that really needs experts to scrutinise effectively. eg the code used in Fergusons study etc.
The whole thing needs more study. Researchers need to provide strong evidence an intervention works. It's how medicine works, the standard of proof needs to be high. Researchers need to have looked for potential contraindications/side effects and no-one is looking for those re. masks.
And works in the environment you apply it to - eg in the community rather than a more controlled atmosphere like a hospital.
eg dialysis machines work to dialyse, but could you apply them to community settings - no of course not!