Perhaps they booked a Disney trip after seeing commercials and online videos of attractions like 7DMT, Splash Mountain, Frozen Ever After and parades like MSEP. So then they do click on the big picture of whats going in the park and with the staggering amount of info and planning needed, they felt overwhelmed.
So when trying to plan their FP+ they wondered why the site/MDE app kept giving them selections with People Mover and Carousel of Progress as 2 of their 3 selections for FP+. In an effort to understand, they call a friend or family member who has visited to get advice. The friend/family member helps out and also tells them about seeing MSEP at the end of the night and how great it was. They tell them to get there early to get a good spot. If that fried/family member is not a Disney aficionado (which most arent) they wont realize that the parade is no longer there after their visit last year or 2 years ago or 5 years ago. So the person planning doesnt think much of it when they dont see it on the times guide (if they even use it). Shame on them though. What a moron for not wanting to create spreadsheets and uber plan every minute of their trip and simply trusting their friends advice.