Point of Order re "young adult"

Just as a point of order, since it has crossed my reading list in ways that prickle my back at least three times this week alone:
Yes, Young Adult sells well right now, but that doesn't mean everything is going to fit the label "Young Adult." 
I do understand the difficulty of deciding, since young adult is used as a label for at least two things: books teens would want to read, and books specifically written and/or marketed for teens.
But specifically, I'd like to note:
1) If the main characters are all under the age of 12, the odds are pretty good the book is not young adult.
2) If the main characters are all over the age of 25, the odds are likewise pretty good the book is not young adult.
3) Not everything teens enjoy reading is "young adult" and, vice versa, not every book published as "young adult" is one that teens will enjoy reading.

And I get that often young adult is currently being used to describe books whose main characters are teenaged, but I object. Sometimes a bildungsroman is just a bildungsroman.  So, I add:
4) The mere presence of teenaged or young adult main characters does not automatically mean a book's main audience is teenage or young adult people.

Ok, I'm less cranky now.  Please return to your regularly scheduled programming.  Thanks.