A quick glance to the history of the article, I see it was edited by multiple usernames and IP address at different times. How did you come to the conclusion that it was self authored?
Funny to think about: "writing your own Wikipedia page without it getting taken down for Original Research" is a fun first hobby project to certain kinds of network-security people, as much as as "making your Github activity graph solid green" is a fun first hobby project to bot programmers.
Because this is a person that doesn't meet the notoriety requirements for Wikipedia, and goes into a level of detail that is also totally unnecessary. It is trivial to connect to different servers via VPN and creating new usernames on Wikipedia takes seconds.
They clearly do meet the notability requirements; the cites on this article are almost as long as the article itself. Notability on Wikipedia is a term of art; it refers ("mostly") to how much of the content of the article can be drawn from (ideally diverse) secondary sources. It's not an achievement award.
Wikipedia has protections against this. it is not trivial. Each change by random ip also has to be accepted by editor with permissions, and getting these permissions is not easy. It might be possible to bypass all abuse counter measures, but it takes a lot of effort and is not trivial
