If I am speaking to a radical environmentalist about the environment, I have to work extra hard to communicate.
For example, if I am agreeable with him, he is tempted to assume that I agree with his entire agenda (I think saving the environment is the most important thing in the world and I would gladly die to save a tree). If I disagree with him, he is tempted to assume I am against his entire agenda (I hate the planet and am trying to destroy it as fast as possible).
The more opinionated he is, the harder it is for him not to paint me with an entirely black or white brush.
If course, that does not mean that I can blame him for my being misunderstood. It means I must work all the harder to clarify and communicate what I mean. Communication is not successful until what is in my mind and heart is properly understood in someone else's heart and mind.