It looks like the "tampering" was mostly just removing the username of the person submitting the links, so they wouldn't get banned by paywall sites, and archive.today has always done this: https://en.wikipedia.org/wiki/Wikipedia:Requests_for_comment...

And it looks like in some instances they changed their own alias to the name of the blogger they're in dispute with, in a fit of pique.

You have to scroll down to get hints because the conversation has been redacted, and the evidence is not provided with side-by-side comparisons.

I understand the ethical concerns about linking to the site but the blanket accusations of "tampering" seem a bit disingenuous, since no article content was ever changed afaik.