Chapter 21 The House Elf Liberation Front is one such major detail. Hermione is advocating for how house elves are owned and reduced to slave labor.
Nobody is on her side. Fellow students and adult wizards agree that the elves accept how they are treated; overworked, beaten, and not paid
Dobby, who was freed by Harry, suffered trying to get a job until Dumbledore hires him. The sock-baring elf bargained for a very low wage and one day off a month from Hogwarts headmaster to limit his sense of freedom. His mere audacity to wear clothes and ask for a wage to work made him all but an outcast in the wizarding world.
"Dobby likes freedom, miss, but he isn't wanting too much, miss, he likes work better."The ultimate message I take from JK Rowling and this particular part of the book is helping others achieve equal rights.
While Dobby is definitely a symbol of liberation and helping other elves achieve it, 99% of house elves accept who they are. House elves punish themselves for even thinking about another way of life. It's only some of the characters who consider/understand their forced labor is wrong. Is it wrong for Hermione to step in and fight for those who don't want to?
Can we face that Ron is sorta the most ignored Weasley son by his mother and brothers? Feeling on the brunt end of jokes and not taken seriously or held in high regard, why didn't Ron have a change of heart and help Hermione with S.P.E.W.? Wouldn't that have made him a more layered and interesting character?
As a reader, the House Elf Liberation Front does add layers to the social justice workings of the wizarding world. But it's also a little arduous and makes the Twi-wizard Tournament have a stop-and-go feel to it.
Is it a necessary chapter to be in the fourth book?