Because there is no error in evangelizing per se. This discussion was started, and subsequently commented on, regarding the methods of evangelizing, and whether there is one technique that is "more right" or "better" than any other technique.
Your point is what's being preached when we evangelize; which is, admittedly, the most important part of why we evangelize in the first place. But that's another discussion. This one was started talking about how we evangelize.
But we can never seem to get to those subjects because someone always turns the conversations around to why Calvin is more right than Arminius, or why neither Calvin nor Arminius are right, etc., etc.
Me, I'm gonna go out and preach Christ, crucified, His blood shed for the remission of our sins. Now how about we talk about whether I do that on a street corner, or via letter, or telephone, or internet YouTube videos, or in prisons, or nursing homes, or just in our churches on Sunday mornings?