As for the possibility of certain groups bloc group voting for her, whether it's her mother's supporters or vote for the worst fans, I don't hold her responsible for that. I've always disliked it when DWTS casts people they know come into the contest with a strong voting bloc already in place (the Osmonds, for instance, though better dancers than Bristol, both came in with strong voting blocs their seasons as opposed to some people who weren't very well known by a lot of viewers and had to make it on the basis of their own talents) or people who have had enough previous dance training to make it difficult for the rest of the cast to compete with them. Maybe DWTS doesn't know that to begin with, but by an all-star season, they do, so DWTS knew what might very well happen when they cast Bristol. So, I hold DWTS partially responsible for that, just as I hold those who vote without even watching or have decided to vote for someone they think is bad just to see how much they can control the show's outcome partially responsible for it. On the other hand, Bristol certainly knew in advance what was likely to happen too and publicly said that she did. So she can't really complain now when people don't like what's happening and get upset with having to watch her, instead of dancers they prefer, advance further into the competition.
Personally, I find it hard to feel too sorry for someone who knows going into DWTS that she's going to be an obvious target of criticism and decides to do it anyway, no matter how young she is. At this point, she needs to recognize that she's not really competitive with the rest of the cast in terms of her dancing and just try to enjoy herself and be as gracious as she can about the backlash she admitted she knew she was going to deal with this time too, because it's what comes with a job she decided to take. Certainly there have been dancers on the show before that haven't been that talented--like Carson Kressley--who were more popular because they didn't expect that the fact that they tried hard or improved was enough to qualify them for the finals. There were likely viewers who didn't much care for Kressley being openly gay either, but he never made that an issue but just did the best he could and was enthusiastic about being on the show despite his difficulty learning the dances. This season, I suspect that Maks and Kristie don't really think they're locks for the finals, but they seem to be enjoying their time on the show anyway. And there have also been dancers who weren't very good at first but tried hard and improved more than Bristol did her first season and were gracious about their deficiencies and honestly did try to do the dance the way it's supposed to be done anyway. I'd say Ty Murray falls into that category, and I believe he actually went out one week before the final three and was perfectly fine with that. Murray never made a big deal out of the fact that he has had enough joint replacements and broken bones to make him less naturally limber than might be best for a dancer or that he had no performance experience either.
Bristol's seeming inability to understand that the other contestants on the show this season are largely much better dancers/performers than she is and the fact that she doesn't seem to be having much fun being there is enough, I think, for people to want her gone for what she's done as opposed to anything her mother's done. Her insistence on viewing this season the same way she viewed her original season--where she also outlasted some better dances--when she felt that the fact that she was improving made people root for her because she was the underdog also just doesn't make sense to some, including me. In an all-star season, there really shouldn't be any true underdogs. They should all be there because they were among the best the first ten seasons (or whatever it's been) had to offer. Last week, for instance, there was some really great dancing from the contestants, and even though it was Bristol's best dance thus far, she still wasn't anywhere near as good as those who scored higher than she did. The fact that she still didn't go home and two past champions did, bothers some viewers just on the basis of the dancing, period.