arsewipe.js

const leftyTwats = ['theoldgreenfascist',
                    'DBC Reed',
            'Liberal Yank',
                    'William Connolley',
                    'Don\'t Hug Me',
                    'Worstall\'s FAIL',
                    'Mister Bean',
                    'Heisenberg',
                    'mr ecks is a cock',
                    'Ecks is a fucking spastic',
                    'meiac',
                    'Jesus Christ',
                    'Newmania',
                    'Ice',
                    'Fatty',
                    'NiV',
                    't it',
                    'Steve.'];
const antiSemiticTwats = ['Dave',
                          'Davedave',
                          'Paul Rain'
                         ];
const justTwats = ['Rickie'
                  ];
const islamicTwats = ['Ahmed Fares'
                     ];

function replaceDrivel (author, commentItem, twat, replace) {
  if (author.stringValue === twat) {
    const comment = document.evaluate (
      'article[@class=\'comment\']/div[@class=\'comment-content\']',
      commentItem, null, XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE, null);

    /* Should just be the one, but replace all just in case */
    for (let i = 0; i < comment.snapshotLength; i++) {
      comment.snapshotItem (i).innerHTML = `<p>${replace}</p>`;
    }
  }
}

const comments = document.evaluate(
  '//div[@id=\'comments\']/ol[@class=\'commentlist\']/li', document,
  null, XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE, null);

for (let i = 0; i < comments.snapshotLength; i++) {
  const commentItem = comments.snapshotItem (i);
  const author = document.evaluate(
    'article[@class=\'comment\']/footer/div[contains(@class, \'comment-author\')]/cite[@class=\'fn\']/descendant::text()',
    commentItem, null, XPathResult.STRING_TYPE, null);

  [...leftyTwats, ...justTwats].forEach (twat => replaceDrivel (author, commentItem, twat, 'Usual twattish drivel'));
  antiSemiticTwats.forEach (twat => replaceDrivel (author, commentItem, twat, 'Usual anti-semitic drivel'));
  islamicTwats.forEach (twat => replaceDrivel (author, commentItem, twat, 'Usual terrorist supporting drivel'));
}