I teach second grade and I've read both classics (such as
The Secret Garden) to them. They can only take the classics in small doses though and prefer the more humourous ones. I actually made them give The Secret Garden a few chapters before writing it off, and by the end most of the kids loved it! But they were ready for the more lighthearted Pippi Longstocking that I read to them next. I try to read aloud books that they wouldn't normally pick up on their own.
Someday, please don't take this as a criticism, but most children, and I'd say more than half of adults look more for entertainment value in books they read than the quality of the prose. I like to read a classic now and then, but usually when I read it's an escape from the real world and I like to be able to get immersed in the characters and story. For every book I read analytically, I read two or three just for fun. Kids are the same way. I teach my kids how to read for meaning and understanding, how to analyze the author's purpose and the plot. However highly regarded the author's work is, when it comes right down to it, kids just want to be entertained.
It's the nature of kids books and movies to have those "mean" teachers and parents and the kids save the world. It's playing into kids' fantasies and desires to have some more independence and have their feelings validated. They know it's not real. I've never had a child treat me poorly because they read about it in a book, it's what they're shown out in society that has affected their behaviors.
Kids definitely need to be exposed to great literature at appropriate ages, but reading is supposed to be fun. I say if it gets them reading, let them have the brain candy. There is plenty of time for them to get into the classics.
ETA: Yes, I have allowed comic books in my classroom as reading books for reluctant readers. Get them hooked, then expand!