Why was Hermione unsympathetic towards the spider?

When Moody demonstrates the cruciatus curse, Hermione tells him to stop---but it's pretty heavily implied that she's only concerned about Neville and not the poor little spider.

I get that it's traumatizing for Neville, but that poor spider was being physically tortured. How could Hermione not be concerned about it? The only two possible explanations I can come up with are a) this is a case of "what measure is non-human", which seems out-of-character for Hermione, or b) she feels awkward showing concern for an arachnid around Ron. I like this second explanation---it's the only one that makes plausible sense---but I thought I'd bring it up in case anyone has any other theories.