It's not user comments, it's a bot network. You'd be surprised how smart AI is when it comes to replying to people. Just look at Reddit. Here's an example, make sure you read the title of the thread.

Politics is extremely botted, especially on youtube. Many times you can go to these accounts and see that they're less than a year old and talking nothing but politics. Youtube has been around forever, people just don't create a youtube account to do that.

Paul should really do a malware and antivirus scan as it sounds like a bot network has infected his PC.