Well, is it good or neutral for you? I've always felt like these diet drinks were just marketing to make you think everything was fine, feel free to drink as many as you want. I've worked with a few people that would go through 4-6 Coke Zeros every day. In no world can I imagine that that wouldn't have negative long term effects on a human -- all things in moderation, right?
Personally, I'll drink a Mexican Coke with cane sugar maybe once or twice a year, knowing it's not great for me and treating it as a dessert.
But I do agree, it's not good reporting. Pretty much no info on the actual scientific research, but hopefully WHO will give more in depth data.