The user helps free the Internet by using archive.is as an openly accessible backup platform.

dude... haha it's a random person on the internet who is doing it for free.

They (archive.is) would have built the extension to send the current page content to their servers and the user would have installed it so they can archive internet pages. https://help.archive.org/help/save-pages-in-the-wayback-mach... (item 2)

You are confusing archive.is with archive.org. Although archive.is does have an extension[1] it doesn't appear to capture any of the page contents, it just simply sends the url for archive.is to crawl.

1: https://chrome.google.com/webstore/detail/archive-page/gcaim...

I wasn't exactly confusing them but yeah, I did link to an archive.org article. I was having difficulty finding something specific to archive.is.

I think the distinction between the two is moot in this post. The question could very well have been "How does archive.org bypass paywalls?" Though it's interesting that archive.is seems to just crawl the URL. Indeed that means they wouldn't necessarily be able to bypass the paywall.