I wasn't initially bothered by Bristol's participation, but I was eventually. Not because of Bristol herself, but for the same reasons that I was bothered by Bobby Bones...voters voting them in despite not being championship-worthy dancers (and in Bristol's case, not having a dynamic personality to make up for it). At least she didn't win, but she still prevented Brandy from making the finals and providing a formidable challenge to Jennifer Grey.
I wasn't bothered by Rick Perry's participation at all, mostly because he didn't bring politics in and didn't go very far. Same with Tom DeLay. If Spicer proceeds similarly then I won't be bothered by his presence either.
The main issue with politicians being on the show goes back to voting. Politicians on DWTS generally do not bring political matters onto the dancefloor; however, they are practically at professional level when it comes to obtaining votes. The other issue is that DWTS has only had conservative/Republican politicians AFAIK. We haven't seen someone liberal be part of the cast, or libertarian, for that matter.