I’m not sure I’d go quite so far as to say “deserves it” since Ponine was only a kid following her parents’ example, but I see what you mean. (If anyone deserved misfortune, it was the ADULTS who should have been looking after a child’s best interests…and pretty much caused Fantine’s death. At least Madame Thenardier died in the novel.)
That’s part of the main thrust of an essay that used to be online called “Eponine is Not Kewl.” Unfortunately, I can’t link to it since it seems to have disappeared. It was written by a fan of the musical and the novel who, nevertheless, points out that musical!Eponine is a somewhat sanitized version of novel!Eponine, and points out the flaws in the logic of the teenage girls who worship her. (She says something along the lines of, “sure, your life is ‘just like hers’…except you eat three times a day, and are warm in winter, and have a decent roof over your heads, and your father’s not a petty criminal who pimps you out to his associates…”)
She explains that in the novel, Marius and Eponine weren’t really friends as they’re portrayed in the musical…she’s just this girl that shows up in his apartment to pick up some letters her dad lost, and he pities her, but is also a little creeped out by her. (He does ask her to be a messenger for him, as in the book, and tries to help her with his last five francs.) She also says that the real tragedy of Ponine’s life is not her unrequited love for Marius, but the fact that she started out with the advantages of any kid, but ended up the way she did.
And she also makes that point you did…that (to paraphrase what I remember), “sure, she has it rough now, but so did Cosette when she was a kid…and who was it who ran tattling, ‘Mommy, she’s touching my stuff!’?”
It kind of tickles me that this show (like the novel) portrays any number of social injustices, and the teenage girls watching it are thinking, “Harsh justice system? Meh. Grinding poverty? So what? Injustice to women? Whatever. Teenage girl getting friendzoned? OMG WORST TRAGEDY EVAR!!!11!!!”
But then, I have to remind myself that the young girls who see this musical are usually in a fairly privileged position (at least if their folks can afford to take them to see a Broadway show), and wouldn’t be able to identify so much with the other problems. But having a crush on a guy who doesn’t notice? That’s something they can relate to.
I’d like to recommend an excellent short story on Fanfiction.Net, Life I Might Have Known. It depicts the life of a young Eponine fangirl, who finds out, as her family falls upon misfortune, exactly what a life like hers would have been like.