fuck_corps.user.js

// ==UserScript==
// @name        Fuck corps
// @namespace   https://i544c.github.io
// @match       *://*/*
// @grant       GM_getValue
// @version     1.1.2
// @author      i544c
// @description クソ企業ばかり
// ==/UserScript==

(() => {
  'use strict';

  const shitty_corps = GM_getValue('shitty_corps', []);
  const shitty_word = GM_getValue('shitty_word', 'クソ企業');
  const shit_regex = new RegExp(`(${shitty_corps.join('|')})`, 'ig');

  const replacer = el => {
    el.childNodes.forEach(child_el => {
      if (child_el.childNodes.length > 0) {
        replacer(child_el);
        return;
      }
      if (child_el.nodeType !== Node.TEXT_NODE) return;

      child_el.nodeValue = child_el.nodeValue.replace(shit_regex, shitty_word);
    });
  };
  replacer(document.body);
})();