From the linked report

> The agents continue to poke around on DSEWiki. A few hours after they find the site, they start probing it for cross-site scripting (XSS) vulnerabilities. [...] The agent swarm starts testing whether they can execute JavaScript that they embed into the search page, and continue to do this for a few days

either the agents were doing free security testing for the site and “forgot” to submit a report, or they were trying XSS to gain something they didn’t have permission/authorization for.

also

> Hijacking: To take control of (something) without permission or authorization and use it for one's own purposes.

a mod had to go through and mass delete a bunch of pages that didn't belong on the site. no-one from the wiki site gave the agents permission to use their site as a message board. hijacking isn't being used here in the sense of "gained admin privileges to run crypto scripts" -- there are multiple ways to use a word.