It's just lazy coding. I assume it is related to the same reason why making raid reruns would be "technically challenging."
Note that lately, DMM has prevented you from seeing Raid Help Requests from an event which front page you haven't visited yet.
So... they didn't bother fixing the problematic code, but they DID bother to make a work-around for it. I assume because their support got "wtf?!?!" messages every single raid event. Just like 10-11 months before we get that feature too! Yay!