If Zuckerberg had not ignored a C&D letter (from the Winkelvosses lawyer), there would be no Facebook.

Once Mr Barclay is no longer using Facebook, then whatever "browsewrap" agreement was created between Barclay and Facebook is arguably no longer in effect. Whatever provisions survive do not include a prohibition on using automation.

The Terms state

"If you delete or we disable your account, these Terms shall terminate as an agreement between you and us, but the following provisions will remain in place: 3, 4.2-4.5."

The prohibition on automation is provision #2.

Even if you believe that Facebook can bind non-users to these Terms, then you also have to consider that most courts have refused to enforce browserwrap agreements to begin with. For websites trying to enforce browserwrap, there is a recurring problem with the question of consent. Generally, the website has the burden of proving the user read and understood the Terms.

But let's assume Facebook can get past this hurdle. Let's consider the "automated means" provision. Is it enforceable. It is unlikely a provision like this one in a browsewrap agreement has ever been reviewed by any court. Facebook's provision is extremely vague and ambiguous. What is "automated means". It is the essence of a computer. If browser extensions are banned, why not state this explicitly. For example, Facebook-approved web browsers without any extensions all use automation to request image and JavaScript resources. Users do not manually request those resources.

The clause itself states

"You may not access or collect data from our Products using automated means (without our prior permission) or attempt to access data that you do not have permission to access."

But the UnfollowEverything extension does not access nor collect data.

It is arguable that (a) for any ordinary user, using UnfollowEbverything does not violate the Facebook Terms and (b) that it is only the usage of this extension by researchers who were otherwise gathering behavioural data that triggered the C&D letter. We already know that Facebook fears researchers studying the effects of its (scripted, automated) website on users.^1

1. https://web.archive.org/web/20210806191005/https://www.wired...

In the Facebook Terms, Facebook itself admits to using automation:

"And we develop automated systems to improve our ability to detect and remove abusive and dangerous activity that may harm our community and the integrity of our Products."

It is 2021, and courts in Northern California are well-aware that automation is useful, for everyone. They would also understand that unfollowing friends results in no loss to user privacy. Nor does it interfere with any ads.

But let's assume Facebook can overcome these hurdles and a court in Northern California agrees with the ridiculous arguments Facebook's lawyers would have to make. Imagine (a) Facebook manages to affirmatively prove Barclay consented to the browsewrap that no one ever reads and (b) he understood that using UnfollowEveryone was a violation of the Terms. What would Facebook claim as damage/loss for Barclay's alleged "breach".

As an aside, this bit in the Terms is amusing

"We do not control or direct what people and others do or say, and we are not responsible for their actions or conduct (whether online or offline) or any content that they share (including offensive, inappropriate, obscene, unlawful and other objectionable content)."

It is easily arguable that Facebook does seek to control/direct what users do as it forced Barclay to spend hours in order to unfollow each of his friends by pointing and clicking.

Facebook attempts to control and direct what users see and do when using the website, rather than allowing users to make their own choices. That seems beyond question.