Counter-Objector

Someone who objects to a Situation or Ideal while applying Logic, Facts, and Evidence to back up their Objections
The "Counter" part usually comes in when the person the Objector is arguing with is usually someone who Objects the same thing, but for a different reason... Usually lacking in reason entirely and just objecting because it's "cool to be different"

Joe is a Counter-Objector because he agrees with Frank that this Political Situation is bad. However, Joe disagrees with Frank on WHY it is bad.