Well... if the photographer is being paid to shoot a particular theme that requires certain mood/emotions to be captured for a particular purpose... then what you say is true. Then you would want to talent scout and find the correct model, get the correct shoot director, MUA, etc... but that's not what's going on.
Take a look at the adverts... lingerie theme, bikini, Sailor Moon... What do you hope to learn from these? What is going on here? The answer lies in Xiaxue's blog. Again, I don't think there's anything wrong here... but I think it's not about photography. I think the organised shoots where you can actually learn about photography are few and far between.