This is India we are playing. You don't lean on them and get away with it. If they didn't want to revoke their appeal, then it wouldn't happen.
That being said, I personally don't think they should have revoked their appeal. Bell made a mistake. It would be an unusual dismissal, but these things happen. However, as Dravid said, it wasn't sitting well with the Indian team so they decided to change their minds, so fair play to them.