Reading more about Jane Austen's books reiterated for me that all the pureblood/halfblood/muggleborn distinction in Harry Potter is absolutely about classism.
A lot of people see class as a group of similar financial levels. But traditional class in England was about your birth, your parents' class, not about money. In Jane Austen's world we have characters like Mrs Smith (Persuasion), Mrs and Miss Bates (Emma) or the Prices (Mansfield Park) who are relatively poor, but they are still gentry. They are not the poor—this is genteel poverty, they are not working class (they do not work physically like some peasants, ugh, they might have some appropriate profession like Church or Army, i.e. Mr Price is a lieutenant of the marines), they are not lower class. They are lower gentry—lower upper class. Unless they marry down or start working, losing money won't take away their upper class. Henry Crawford may propose to Fanny and Edmund may marry her without any problems, because, though poor, she's still a gentleman's daughter. (Technically. I mean, Mr Price isn't very gentlemanly, but he still belongs to that class.)
In Harry Potter the Weasleys' bad financial situation doesn't mean they are working/lower class. They are upper class—lower (poor) upper class (pureblood). When Hermione marries Ron, she marries up in that world.
Racism has nothing to do with it.
