The answer is no, you can do the 10 pound Keto Challenge completely without it and have amazing success doing so! The challenge area alone will help you succeed.
But.......
To get the most out of your purchase I highly recommend activating a facebook account if you don't have one. You don't have to follow people, or even do anything special with it. You just need to be able to access the challenge community and be able to activate the accountability and coaching program though messenger.
Having support of the group and going through the accountability and coaching program is what makes this challenge like nothing else out there. So if I were you I would make sure to have a facebook.
But.......
Again, its not a must and you do NOT need to do it if you don't want to.