$words = array('xxx,yyy,zzz,etc..');

$words = array('xxx,<p>yyy</p>,zzz,ddd');
 $pattern = '/(?:' . join('|', $words) . ')/i';

<p> </p>

<p>xxx</p><p>yyy</p><p>zzz</p>

case 'OnBeforeCommentSave':

        $comment = $modx->event->params['TicketComment']->get('text');

        $output = $matrous->filterText($comment);

        $modx->event->params['TicketComment']->set('text', $output);
        break;

if ($resource->get('template') == 24) {
        if (!$resource->content) {
                $resource->set('published', 0);
        }
        }

if ($resource->get('template') == 24 && !$resource->get('content')) $resource->set('published', 0);

$resource->save();

$words = array('xxx', 'yyy', 'zzz', 'etc..');
$pattern = '/<p>(?:' . join('|', $words) . ')<\/p>/i';
$content = preg_replace($pattern, '', $content);

<p>xxx</p>

case ' OnBeforeDocFormSave':
        /** @var TYPE_NAME $resource */
        if ($resource->get('template') == 24) {
        if (!$resource->content) {
                $resource->set('published', 0);
        }
        }
        
        $content = $resource->get('content');
        $words = array('<p>xxx</p>', '<p>yyy</p>', '<p>zzz</p>', '<p>ddd</p>');
        $pattern = '/\b(?:' . join('|', $words) . ')\b/i';
        $content = preg_replace($pattern, '', $content);
        $resource->set('content', $content);
        $resource->save();
        break;

if ($modx->event->name != 'OnBeforeDocFormSave') {return false;}
$content     = $resource->get('content');
$words = array('xxx', 'yyy', 'zzz', 'etc..');
$pattern = '/\b(?:' . join('|', $words) . ')\b/i';
$content = preg_replace($pattern, '', $content);
$resource->set('content', $content);