There's really no interpretation of this which isn't malicious, although, not to defend this behaviour whatsoever, I'm not entirely surprised by it. The only real value of archive.is is its paywall bypassing abilities and, presumably, large swaths of residential proxies that allow it to archive sites that archive.org can't. Only somebody with some degree of lawlessness would operate such a project.
Not excusing this malicious behavior, but I have to say, the mentioned blog post is a major dick move, too. Got quite the impression of a passive aggressive undertone, and there is clearly bittersweet irony in collecting and "archiving" an archiver's personal information from long ago traces. Maybe it's all some feud between two dicks, some backstory untold. Maybe the blog author wanted some information gone from archive.today, but was denied.
It's not just for paywall bypassing. Sometimes there are archive.today snapshots that aren't in the Wayback Machine (though I think your overall point about lawlessness still stands).
For example, there was some NASA debris that hit a guy's house in Florida and it was in the news. [1] Some news sites linked to a Twitter post he made with the images but he later deleted the post. [2]
The Wayback Machine has a ton of snapshots of the Twitter post but none of them render for me. [3]
But archive.today's snapshot works great. [4]
[1] https://www.bbc.com/news/articles/c9www02e49zo
[2] https://xcancel.com/Alejandro0tero/status/176872903149342722...
[3] https://web.archive.org/web/20240715000000*/https://twitter....
[4] https://archive.md/obuWr