That's not present on another omglol site that was linked elsewhere in the thread, though.
I would agree with you if they automatically set this for everyone. I'm not sure how come that other sites aren't showing up in the archive. (I'm not a customer of theirs or anything, I'm already hosting my own stuff)
This blocking of the archiver may be philosophical, but not a disgreement. Just speculating, but on the fediverse there are quite a few people who feel their social interactions are personal and 'in the moment'. Something akin to the Cozy Web [0] though not being too strict about (everything is still public after all).