Strong agree. When you become a scientist, you don't give up your right as a citizen to argue for/against policies. In fact, given our knowledge of the subject, it would be natural for us to have strong opinions about policy.
I think the key is to make explicit when you're talking about scientific facts (these are the things that scientists do know more about) vs. normative policy goals (there's no basis for thinking scientists have a more informed opinion).
An edge case occurs when talking about scientific facts (that have right/wrong answers) but are outside of your particular expertise. Don't shy away from areas adjacent to your expertise, just do enough research so your view reflects the opinions of the expert community.
