One strong example of this is Bill Nye and his recent debate with Ken Ham. In an ill-advised move, Nye chose to participate in a debate with Ham putting up creationism against evolution. Not only does this elevate the creationist theory into the field of science, but this may have alienated people who believe in creation from science in general. Scientist for the most part have no problem with people believing in creation. However they do have a problem with it being considered science, as it is quite clearly not (Dart, 2014). It has been disproved hundreds of times over with the most obvious example being that the earth is most definitely older than 6000-10000 years. Elevating creationism into science by including it in a debate has always been something that the majority of scientists have frowned upon and scientist advocates like Nye have hurt the field of science as a whole by participating in creation/evolution debates in the first place.
Perhaps there is a way to keep be advocates and scientists without many negative consequences, but it is safer, for the sake of science as a whole, to remain objective and seek only to pass on the knowledge acquired from research.
Oh the irony of writing this.... Look at me! I'm a scientist advocating not being a scientist and advocate.
The Billy Nye v Ken Ham debate
Various media on the topic including news broadcasting and online papers
Dart, T. (February 5, 2014). Bill Nye 'the Science Guy' debates Australian creationist on evolution. The Guardian. http://www.theguardian.com/science/2014/feb/05/bill-nye-science-debate-australian-creationist-ken-ham