the allowed html tags are difinde in a global array in /wp-includes/kses.php;
to remove them, set the array content to nothing;
by adding some code like this to functions.php of your theme:
/*
* Kses allowed HTML elements.
* /wp-includes/kses.php
* @global array $allowedtags
*/
global $allowedtags;
//remove html tags for comments by setting the array to empty
$allowedtags = array();
/*
*/
to remove the text ‘You may use these HTML tags and attributes: ‘ or so, you might need to edit comments.php of your theme, and find comment_form()
( https://codex.www.ads-software.com/Function_Reference/comment_form ) – then change to:
comment_form(array('comment_notes_after' => ''))
