For all the legal people here, what's the legality of something like "Return YouTube Dislike"? https://chrome.google.com/webstore/detail/return-youtube-dislike/

For all the legal people here, what's the legality of something like "Return YouTube Dislike"? https://chrome.google.com/webstore/detail/return-youtube-dislike/gebbhagfogifgggkldgodflihgfeippi https://chrome.google.com/webstore/detail/return-youtube-dis...