You might call it mild stupidity - and that may be accurate - but I'd call it being human.

Humans react differently to the same information based on how it is presented. It seems to me that activists - specifically those on the left - often fail to take this into account.

I almost always agree with those activists. I certainly agree about global warming. But - pragmatically - if your goal is to convince skeptics, you ought to be very concerned about tone. For better or worse, how you tell your story is at least as important as the evidence backing up your story.

The problem is that a lot of people simply refuse to listen. That would require them to acknowledge that their comfortable lifestyle is unsustainable and needs to change to something less comfortable.

If you agree, why don't you think of yourself as an activist?

Being an activist implies that one proselytizes or at least takes an active role. I do neither so I'm not an activist.