And it is backward and time-consuming. I don't understand why so many people in the Perl community are still wanting to use it.

IRC has helped me for a lot of projects where I collaborate, and where I had questions. I admit it's only really useful if you are logged in permanently. I use it in a tmux session on one of my servers.
I also admit that platforms like slack have advantages (easier sharing of files, showing online status), but also disadvantages.
I can use IRC in textmode, the status line is always visible and it will simply highlight the "windows" that need my attention. No pop-ups required. I can do everything with my keyboard in one terminal window with currently 30 channels.
Browser apps have improved, but I still need to use the mouse a lot.