Louis Barclay the extension author felt that unfollowing everything improved his Facebook experience and helped him break his Facebook addiction. Louis wrote this extension so other people could try this and enlisted a Swiss University to conduct a study to see if this improved user satisfaction with Facebook.
Facebook not only took down the extension but banned the personal Facebook account of Louis Barclay and ordered that he never make any tool that interacts with Facebook, which he felt was heavy handed but as a UK resident felt unable to seek legal redress as in the UK if one loses one is liable for the opponents court costs.
Here is the Slate article by Louis Barclay.
https://slate.com/technology/2021/10/facebook-unfollow-every...
and an opinion by Cory Doctorow on the utility of Unfollow Everything, the study and heavy handedness as a tendency of Facebooks to squash research it doesn't like.