I definitely agree. Back in school I learned that a Newbury medal in a book meant that a dog and/or parental figure will die. I feel like it's easier to make people feel something when the feeling is bad. Also joyful things are sometimes thought to be lesser or simple.
If anyone is a fan of scifi I recommend checking out Becky Chambers. A Psalm for the Wild Built is an optimistic solar punk book that will warm your heart.