Yeah, and I'm still not sold on Shriek having to roll to hit. Not that red shirts are authoritative or whatever, but they are necessarily very knowledgable, and the local redshirts near me have universally stated that Shriek does not roll to hit, and actually thought I was crazy for suggesting that it might. Also, I've never played against someone who thought that it did roll to hit, whether that was in their favor or not. The only conversation I've had where it was suggested that it didn't, was here with GML. Now, GML is very knowledgable himself, and has certainly risen to a point of prominence within the community, but that doesn't make him an authority per se.
After scouring the internet, I have found that many tournament FAQs do specify that Shriek rolls to hit (at the very least, this establishes that the confusion is reasonable, and no matter how you personally think it works, the other guy isn't an idiot for disagreeing with you). However, these tournaments also do things like force ranged D weapons to have a -1 on the table... so it's hard to tell if making Shriek roll to hit is strictly their interpretation of RAW, or a balancing measure they have decided to take above and beyond RAW.
I guess the Shriek (and, I suppose Laugh of Sorrows, as well) debate is one that can't really be finalized without some official word from GW... which we can be well sure will never come. I'd say, have your LGC make a decision and play it that way.
Personally, I don't think it's overpowered to say it hits automatically. Much of the time, it gets no wounds, and the short range and low casting cost means it can be fairly easily denied, and retribution can be exacted in return. No one has finished a game with me and said "Psychic Shriek just tabled my army, it's so broken."
But... play it how you will.