I see your point, but I wonder if the audience as a whole already do sympathasise with her. I don't know of course but the views within the fandom are only a small percentage of viewers and even then as you say there may be many that don't sympathise with her but there are still many that do. At the moment I would even speculate that generally the sympathy is relatively fairly distributed in terms of the triangular nature of this storyline.
The fandom is most likely a microcosm for viewers as a whole. Anyone who comes to a message board to discuss a show is presumably going to be more involved than the casual--or even average--viewer, but just because people don't come to message boards to discuss a show doesn't mean they don't hold similar opinions to those that do.
Again, I said in the eyes of many fans Lindsay is unsympathetic. There are many who like her; there are many who don't. I simply posited that seeing her wrestle with unrequited love for Danny might make her more sympathetic in the eyes of those who might not think much of her, as opposed to say, watching her stand Danny up for dates or blow him off when he tries to talk to her.