Of course they do. I didn't say there was anything wrong or immoral about this. Maybe slightly unethical - creating false perception of public consensus - but then, anyone who lets some random comments shape his political views is an idiot anyway and what they think doesn't matter that much.
On the other hand, when it comes to technical and scientific stuff - like Bitcoin - there's absolutely nothing unethical about correcting common misconceptions. In fact, I wish someone knowledgeable commented on that random "Bitcoin is a scam" blog post that made me miss out on early adoption, when I googled Bitcoin in 2010.