You do realize that proposing that NVC is a cancer is a negative and threatening statement, right? (Cancer is generally considered negative, being that it's a fatal disease...) People who don't already agree with you are going to have a negative emotional reaction to this and immediately disagree without trying to understand your point of view.

If you are trying to convince someone of your opinion, you are failing. If you are trying to assert your opinion forcefully without caring what others think, you are succeeding.