Silly Protests

People demonstrating for tougher political measurements against climate change have glued themselves to the UK Energy Department.

I do not really understand protests like this, not in a democracy with freedom of speech. Is it not better to try to convince people by stating facts and arguments, rather than just sitting in the way of people? The cause against climate change is important, but I think it is too important for protests like this. I fail to see how these protests can convince anybody. I hope I am wrong, that people get convinced, but I do not know how they would be. People are not very wise, sometimes.