Agree!
Recently I heard Dr. Hilary Seligman, who's work involves food insecurity, speak on a panel about this exact question. Can researchers be advocates? Her response was simple, straightforward and stuck with me. We all have different hats that we wear in our lives- we have our research hat, our advocacy hat, our physician hat, our regular person in the world hat. As long as we are clear about what role we are in I think researchers can definitely speak out in realms that are beyond academic papers and conferences.
While we may not be able to say, "this is what my research shows, and you should vote this way" , I think we are empowered to say for example, "my research shows that sugary beverages increase your risk of diabetes" in a forum that is discussing imposing a sugar sweet and beverage tax. Being clear about the boundaries that come with each of your "hats" can help balance the role of advocacy and objectivity.