The parent commenter is saying that JavaScript in the browser MUST NOT be a dependency for core functionality because it may be disabled ("when JS cannot JS").
If your site is popular over Tor — that is, if it's used for warez or by whistleblowers and journalists who need to browse privately — this may be good advice. If it's not, people who disable a core aspect of the browsing stack are savvy enough to enable JavaScript on a site-by-site basis when necessary.
If your site is popular over Tor — that is, if it's used for warez or by whistleblowers and journalists who need to browse privately — this may be good advice. If it's not, people who disable a core aspect of the browsing stack are savvy enough to enable JavaScript on a site-by-site basis when necessary.