Here's the original post with the evidence of u/maxwellhill being Ghislaine Maxwell. The post was featured in an article by the Daily Mail. I have edited this post for corrections, readability, broken links, and included more research.
I am now certain that the account was operated by Ghislaine Maxwell.
https://old.reddit.com/r/conspiracy/comments/r45a5n/here_is_the_evidence_that_reddit_user_maxwellhill/
User is a Redditor since 2006, first one to collect 1 million karma, now 12th most link karma (8th when posts ceased), and a "Charter Member".
Maxwellhill was a very active reddit user who produced highly upvoted posts but there has been no posting at all since Ghislaine Maxwell was arrested.
Evidence:
Posts nearly every day for 14 years up until Ghislaine Maxwell's arrest.
Gaps in posting line up with Maxwell's mother's death and the Kleiner Perkins party where former Reddit CEO Ellen K. Pao reported seeing Maxwell and the TerraMar Project speech.
User claims to be born in December and Wikipedia shows Dec. 25th birthday for Maxwell
Someone says "Winter doesn't start until Dec. 21" at which point Maxwellhill states their birthday is after Dec 21.
Posts articles about why we should legalize child exploitation material
Gripes about over-zealous child protection laws
Discusses age of consent in various countries here and here
Moderator of r/environment & small subreddit r/enviroaction; many posts about ocean protection (The Terramar Project, anyone?)
"Maxwellhill" may be a combination of her surname and the family estate in the UK, Headington Hill Hall
Account spams strictly liberal propaganda, but doesn't seem to have mentioned anything Epstein related.
User is not some other person from Malaysia as r/worldnews mods have said here and here
Maxwellhill says she only visited Malaysian countries.
Maxwellhill AMA strongly suggests user is British by the terminology she uses. For instance, their favorite word is "Bollocks" and the use of English colloquialisms. That the user claims to be male is likely an attempt to remain anonymous, which is not surprising, since she was a sex trafficker and child groomer for Epstein. The user never revealed her true identity in any interview or post, but left clues.