Nah, people who support nullification based on perception of the specific case and offender circumstances are not generally less logical and articulate than others.

You obviously want to eliminate people who either see the law as inherently just or see it as important to uphold the law even when the result would be unjust, as well as people inclined to see punishing your client as just despite the circumstances. But there's no reason, in general, to think that logical thinking or articulateness are, in general, going to be good correlated for those moral inclinations.

The point is that smart people are not always dismissed. Different legal strategies work better with different jury selections.