Place this file inside a new hide_comments folder in your backend livewhale/clients/modules folder.

private.application.hide_comments.php

<?php

/*  Hide Comments

    This application hides the Comments checkbox on all editors in
    the LiveWhale backend management interface, except for admins. */

$_LW->REGISTERED_APPS['hide_comments']=array( // register this application
	'title'=>'Hide Comments', // the module name 
	'handlers'=>array('onOutput')
);

class LiveWhaleApplicationHideComments {

  public function onOutput($buffer) { // make changes to backend page buffer before widget processing
    global $_LW;
    if (substr($_LW->page, -5) === '_edit' && ((method_exists($_LW->d_framework, 'userSetting') && !$_LW->userSetting('core_admin')) || $_SESSION['livewhale']['manage']['is_admin'] !== TRUE)) { // check that the user is on an editor page and not an admin
      $pattern = '~<input([^>]+)name="has_comments"([^>]+)/?>\s*Allow users to post comments\s*~imsU';
      if (preg_match($pattern, $buffer, $matches)) {
        if (strpos($matches[1], 'checked="checked"') !== FALSE || strpos($matches[2], 'checked="checked"') !== FALSE) { // check to see if comments are enabled
          $matches[0] = str_ireplace('type="checkbox"', 'type="hidden"', $matches[0]); // change the field to hidden
          $matches[0] = str_ireplace(' checked="checked"', '', $matches[0]); // remove the checked attribute
          $matches[0] = str_ireplace('Allow users to post comments', 'Comments are enabled.', $matches[0]); // change the message
          $buffer = preg_replace($pattern, $matches[0], $buffer); // and update the page
        } else {
       	  $buffer = preg_replace('~<fieldset[^>]*class="[^"]*comments[^"]*"[^>]*>.*</fieldset>~imsU', '', $buffer); // find the entire comments block and remove it
        }
      }
    }
    return $buffer;
  }

}

?>