However you feel about jury nullification, I'm sure you wouldn't be so happy about reverse jury nullification -- where the law contains a loophole, the jury agrees the accused falls into the loophole, but convicts him anyway because the thing the loophole is stupid. (Not that there's anything inconsistent in this position. Just remember, many crimes have victims.)
Personally, I believe that in an ideal world, jury nullification would be a serious evil. However, our world has some massively screwed up laws, and refusing to enforce a bad law is a virtue.
As Arrow said, this is harder to do, also there are cases where people should NOT be falling through those loopholes, and i am glad that Juries can make sure those people are punished.