So I replied to MJ12Bot's reply [1] outlining everything I've mentioned so far about the sheer number of bad links they're following and how their explanation of “//” wasn't correct. They then replied:
From: Majestic <XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX>
To: Sean Conner <sean@conman.org>
Subject: [Majestic] Re: Your robot is making bogus requests to my webserver
Date: Fri, 12 Jul 2019 07:27:48 +0000
> ##- Please type your reply above this line -##
Your ticket reference is XXXXX. To add any comments, just reply to this email.
> * * * * *
I can tell from your responses that you are much better than us, so we can only continue to avoid visiting your site.
Kind Regards > XXXXX
I guess this is their way of politely telling me to XXXXXXXX. Fair enough.