I forgot to respond to the other half. I agree with you that Muggle-born kids should be more bothered than they apparently are. We don't see Hermione doing this directly, that I've noticed, but the extent to which she's assimilated is really quite creepy. I think I really first noticed it when she was taking Muggle Studies, then again in GoF when she talks about "Muggle substitutes for magic." She seems to have forgotten that she used to be one of them. Harry has, too, but he has no positive connections to the Muggle world, so it's less surprising. These are the only Muggle-raised kids we know well enough to know about this. I like to think some do care.

I wonder what Mr. Finnegan thinks of the Wizarding World. Seamus tends to act more like a pureblood than a Muggle-born, which suggests his upbringing had very little "Muggle" to it. Was Mr. Finnegan expected to assimilate, too?