It is also still just one study. It's an outlier in comparison with other studies and as the article you linked mentions, the study measured girls soccer concussion rates massively higher than boys.

From the study: "To our knowledge, this is the first study to report that concussions now account for a higher proportion of injuries in girls soccer than boys football. The concussion rate for girls soccer is also increasing rapidly, and is now nearly tied with boys football and 3-fold higher than boys soccer."

So if you actually want to use the women's soccer data to measure against football with the differing sports unique susceptibilities to concussions being contested, you would need the nonexistent data on female football players.

Regardless, US Soccer introduced a stupid heading ban for u13 players.