Jamie,

I do not doubt that there are some academics who are cautious about their affiliations with certain groups, and may refrain from taking a stance that they feel could be seen as a compromise to their quest for objectivity. I personally chose not to join either the SCV or the SUV (both of which I am eligible for and have friends and relatives in) because I felt that the groups were too subjective for my taste.

That said, one of my professors years ago was a proud member of the SCV (among other things).