A couple thoughts. First, why do the anti-vaxxers use non-peer reviewed "studies", "articles" and Tik tok as "proof" of something that reinforces their bias, but reject studies that don't, even if they have been peer reviewed? Second, who are these people who did this "study"? The answer for people like Grace is "who cares if it supports my position".
Most importantly, though, what did this study actually do and what did it actually find? Well, it found that wearing masks did have a significant impact at the youngest age groups that it analyzed. It also looked only at kids 3-11, which is obviously very different than dealing with middle and high school kids in the US who move from class to class and social interaction to social interaction all day long, rendering single classroom protective measures far less effective. Furthermore, it noted that vax rates for students in Catalonia is much, much higher than in the US, except at those younger age groups where vaccination requirements do not apply. In other words, it looks very much like a combination of vaccination and mask wearing is very effective where vaccination rates are lower like, um, the U.S.
Do you want to know what other evidence supports this conclusion? Well, the equestrian would know the answer if she actually read the article. Or maybe she did and, rather than just being an easily duped idiot who relies on twitter soundbites, she's intentionally misleading people because she knows her fellow anti-vax/maskers don't read and couldn't understand it even if they did. Regardless, her "study" references another study involving the dumbest state in the US - Arizona - and guess what that study found? It found that the odds of an outbreak in K-12 in AZ were 3-5x higher without an early mask mandate than with. So shocking. It also quoted the following from yet another US study "By analysing 520 counties during the first two months of the 2021-22 academic year in the USA, it was found that those counties without a [mask] mandate presented greater increases ni paediatric [Covid-19] cases." The study also admitted that in Spain they have shitty masks. In sort, if the equestrian actually read the article, she would know this "study" is a minority view and is apparently contradicted by every single study that analyses mask effectiveness in the United States, where vax rates are much lower and masks therefore a more important part of a school system's ability to limit Covid transmission. So why has she reached a definitive opinion knowing that - at best - for her most studies reach the opposite conclusion?