That is horrendous and it should be taken down due to obvious non-fair and possibly malicious intent.
There's nothing you can do to prevent this except devise a system where it's inconsequential to register all of these names: namespaces.
If it bothers you that one person can do this with many packages, then presumably it bothers you that 100,000 people can do it benignly with a few package names which is what goes on in npm/ruby/cpan. The solution is to simply making them worthless.
Subreddits have the same problem.