The survey is a failed experiment, and there is something disturbing in the fact that it was even attempted. The problem is more basic than a bias towards one half of the Divide. The assumption - or shall I say, the pretension - that philosophy is a "profession" and that there is value in polling what the "experts" think about the issues, is the root cause of this travesty. 

Philosophy is not a profession.  Why? Because a professional is one who has a specialized function in the division of labor that characterizes almost all human endeavors. Professions come to be when human groups face certain challenges, and a sub-group takes upon itself the responsibility for dealing with a specific aspect of those challenges. Now, what is the philosopher's function in the grand division of labor of humanity today? A few centuries back, when philosophy was indistinguishable from science, you could claim that philosophers' function is in basic research - dealing with the challenge of sheer human ignorance about the world. Alternatively, many philosophers were, and are today, social and cultural critics. It would be fascinating to further develop the discussion on this particular function of being a critic - is it a profession or a calling? are revolutionaries professionals? - but I won't do that here. Suffice it to say that nowadays, sadly, philosophy in academia is a fossil of its former self, a vestigial structure in modern society just like the vermiform appendix is one in the body. The fact that some people who are called philosophers get paid for it is meaningless - it's not unlike the body "investing" living tissue and some blood into the appendix.