Why is the left attacking Bristol Palin, but gives Ann Dunham a pass?

Question

Why is the left attacking Bristol Palin, but gives Ann Dunham a pass?

Answer 1

the same reason they bash Gov Palins parenting skills but give Joe Biden a free pass

You know, the only VP candidate in this race that has a child with an arrest record.

Answer 2

  Republicans are playing the victim card about Palin.  Don't be a VP if you want to stay out of the news.