It probably does, and you'll find lots of ISPs, VPS and hosting providers also forbid IRC servers. The main reason for the blanket ban is that once upon a time (and perhaps still) IRC servers were widely used for malicious bot command and control systems and it's easier to just forbid them at all than pay people to spend their time sorting the good guys from the bad guys.

Even legitimate IRC servers are DoS attack magnets.

You know, I just checked, and they seem to have been removed those references. But from what I recall the reference was explicitly IRC. I remember thinking, "Why IRC?"

The levels of salt and free time available to the most dedicated of IRC users when slighted is a sight to behold.