There's no doubt, that without lists, many magazines and even newspapers would struggle to keep their readers interested. Yes, people read the news, and articles, but put the 'Ten Best' or '50 something you should do before you something else' at the top of a piece, and it will almost guarantee that it'll get read.
But I have a feeling that what turns up on these lists makes the items self-perpetuating. Let me give you an example of what I mean. I've just come across a list 50 Books All Kids Should Read Before They're Twelve. To begin with, there are some 'magic' words in this title: 'all,' 'should,' 'before'. All relatively innocuous words, common words. But look at the effect they have here. Our attention is immediately grabbed by them. If all kids need to do this, then my kids need to do it. And they need to do it before they're twelve! Wow!
But look at the list. You'll find a great many of the titles on other lists of children's books. Not only are these books already well-known, but every time they get on a list like this they become more well-known. We have to remember this is one person's opinion, and they probably put the list together one day off the top of their head.
Remembering that this is a list for children not yet aged twelve, so look at some of the titles. The Hobbit sits next to Tales of a 4th Grade Nothing (by the wonderful Judy Blume). I am Matala and Revolution is Not a Dinner Party are only a few books apart. Both pretty earnest sounding titles, and seemingly there to broaden the child's social consciousness. I don't think I even had one of these until I was in my mid-twenties.
The Diary of Anne Frank is also there, a book that I'd think was a bit too adult in many ways for even a 12-year-old - unless it's an abridged version. And then The Fellowship of the Ring. Man, I've read this twice, and the second time I found it harder going than the first. This title is followed by The Hunger Games. Crikey, that's a very strange book, with its strong focus on killing innocent people, and its concerns seem a bit beyond even mature 12-year-olds. At the end of the list, To Kill a Mockingbird, which, while it's a great story, is also very longwinded. It certainly has children as the central characters, but it's not truly a kids' book, even though thousands of American schoolchildren have found it on their reading lists.
I've just had a look at another list, 50 New Zealand Books Every Kid Should Read by Age 12. This is quite a mixed bag, and even though I've grown up in NZ, and so have my children, many of these books are unfamiliar to me. The compilers don't claim any authority on this list, which is good, and as it should be. At the end of the day, children are all different and their reading levels will vary enormously, as will their emotional experiences in terms of reading particular books.
I think, personally, that we should follow the Alan Jacobs' approach and read on whim. That's certainly what I did as a child, and continue to do as a nearly-seventy-two-year-old. Claiming that there's any definitive list is probably more of a media approach than a real one.
By the way, you can find some discussion - from a NZ online newspaper - on the first list I've mentioned above, including some reservations about some of the choices.
And a second BTW: I don't see any of my books on these lists. That surely must be an oversight...