Instead of disabling or deleting xmlrpc.php in WordPress, replace it with this file, which would serve one of several sarcastic error messages at random.

xmlrpc.php

<?php $possible_messages = [
  
'Nope', 
'Go away', 
'Nice try', 
'XML-RPC requests on this server have been disabled cuz of people like you. This is why we can\'t have nice things.',
'We don\'t serve your kind here', 
'<img src="//i.imgur.com/oeLBdQJ.png">',
'<img src="//i.imgur.com/ZZW6M6P.gif"><hr>Did you really think an xmlrpc.php attack would work on this site?',
'<img src="//i.imgur.com/OkQFngF.png"><hr>Get off my site! (And stop trying to access people\'s xmlrpc.php files.)',
'<img src="//i.imgur.com/RcHkMC7.gif"><hr>No. XML-RPC has been disabled for this site.',
'<img src="//i.imgur.com/1AKViaj.png"><hr>No. XML-RPC has been disabled for this site.',
'<img src="//i.imgur.com/kdTNhuY.jpg"><hr>But seriously, stop. XML-RPC attacks are annoying and you should feel bad.',
'My reaction when someone tries an XML-RPC attack on my site.<hr><img src="//i.imgur.com/Tk3APxs.gif">',
'<img src="//i.imgur.com/ljEqWmk.gif"><hr>Get outta here. XML-RPC has been disabled cuz of people like you.',
'My reaction when someone tries some lazy XML-RPC attack on my site.<hr><img src="//i.imgur.com/IofYoIz.gif">',
'<img src="//i.imgur.com/RWzzFjA.png"><hr>Nope. XML-RPC has been disabled for this site.',
'My reaction when someone tries some lazy XML-RPC attack on my site.<hr><img src="//i.imgur.com/SITsBuA.jpg">',
'My reaction when someone tries some lazy XML-RPC attack on my site.<hr><img src="//i.imgur.com/74CUe1P.png">',
'My reaction when someone tries some lazy XML-RPC attack on my site.<hr><img src="//i.imgur.com/6kqeQll.gif">',
'<img src="//i.imgur.com/bCcFoap.jpg"><hr>Stop. XML-RPC has been disabled on this site cuz of people like you.',
'My reaction when someone tries some lazy XML-RPC attack on my site.<hr><img src="//i.imgur.com/QQPMKoV.gif">',
'My reaction when someone tries some lazy XML-RPC attack on my site.<hr><img src="//i.imgur.com/moFDZH6.png">',
'<img src="//i.imgur.com/jf5UY0k.jpg"><hr>XML-RPC has been disabled for this site. Don\'t even try.',
'My reaction when someone tries some lazy XML-RPC attack on my site.<hr><img src="//i.imgur.com/IgEhZhf.png">',
'My reaction when someone tries some lazy XML-RPC attack on my site.<hr><img src="//i.imgur.com/QJ6cxoA.gif">',
'My reaction when someone tries some lazy XML-RPC attack on my site.<hr><img src="//i.imgur.com/fjiLpcA.jpg">',
'<img src="//i.imgur.com/4aizxP8.jpg">',
'XML-RPC has been disabled on this site.<hr><img src="//i.imgur.com/iuATSiZ.jpg">',
'XML-RPC has been disabled on this site. Go away.<hr><img src="//i.imgur.com/gukzAyD.png">',
'My reaction when someone tries some lazy XML-RPC attack on my site.<hr><img src="//i.imgur.com/vofBgP2.gif">',
'<img src="//i.imgur.com/dovYD9G.png"><hr>XML-RPC has been disabled for this site.',
'Get lost'

];$message = $possible_messages[mt_rand(0, count($possible_messages) - 1)];?>
<span style="font-family: monospace;"><?php echo $message; ?></span>
<style>img{display:block;margin-bottom:5px}hr{visibility:hidden;margin-bottom:-1px}</style>