I understand your frustration and I apologize for reading into your comments something you didn't mean. I, too, wish people would say what they mean and mean what they say, and that when you say something its taken to mean what you said.

Unfortunately very often people will make a very reasonable (even factually true) point as a preamble to support something very unreasonable. If you agree with the reasonable point the person will then act like you agree with the unreasonable one. This is not only more time consuming and tiring to argue against, it also lends a great deal more credibility to the unreasonable point than it is really owed. To the uninformed reader to looks like the two sides of the argument partially agree, when nothing could be further from the truth. Its immensely frustrating to have your words used against you like this, so many people try and preempt it by jumping straight to (what they assume to be) the unreasonable point and arguing against it directly.

This is toxic for actual discussion. It means that good faith actors have to add all sorts of qualifications and clarifications about where they stand before they say anything about anything, which is tiring in itself. But its the world that we live in. If someone makes an unqualified comment about the CO2 emissions of volcanoes in a thread about anthropogenic climate change people are going to assume that they don't think climate change is real. And, operating that way, those people will be right more often than they're wrong.