Unfortunately there's nothing you can do, users only get permanently banned if they get reported for spamming the homepage, the webmaster doesn't care about someone making racist or discriminatory comments.
You can try e-mailing the dev at [email protected] but again, don't expect a reply or for the user to get banned. Also even if they do get banned they can just make a new account.

Please guys its your website so please report @michi
https://www.mangago.me/home/people/5617274/comment/?page=22
Ik it's a RAGEBAITING account but SHE'S MAKING RAPE JOKES AND DEMANDING RAPE FOR LITTLE BABIES, KILLING THEM AND ALSO IS SUPER RACIST (my english is poor)
Pls like pls someone report it to dev and ban haer
It has became unbearable now
Pls
https://www.mangago.me/home/people/5617274/comment/?page=22