Well, with a question like this you are bound to get a whole load of different answers - you might want to consider moving this into the discussion post to gain a wider range of answers. For me, the background information we are given about Miss Emily and in particular the relationship with her father makes her a figure to be sympathised with rather than a figure deserving of blame. Consider what we are told about her father and her relationship with him:
None of the young men were quite good enough for Miss Emily and such. We had long thought of them as a tableau, Miss Emily a slender figure in white in the background, her father a spraddled silhouette in the foreground, his back to her and clutching a horsewhip, the two of them framed by the back-flung front door.
Note the inference that is made in this quote: Miss Emily's father was such a tyrannical figure that he chased away all potential suitors with his horsewhip. The description in this quote emphasises the fragility and innocence of Miss Emily, describing her as "slender" and in "white", with her father being described in terms that emphasise his violence and control over Miss Emily.
Therefore, although the grisly ending of the story cannot be excused, we can certainly understand Miss Emily's desperate desire to have a husband and to love and be loved - whatever the cost or whatever she needs to do to achieve this.