Is this directed at Doug? I can offer two reasons I participated in that thread.
1. At every opportunity, I trumpet social research that contradicts common sense. There is a huge archive of social psychological research that documents how changes in social context precede changes in popular attitudes. Call me an Enlightenment dreamer, but I think reasoning guided by evidence rather than dogma is a beautiful thing.
2. I've been in enough "diversity training" in my college gigs to know that persuasion is an ineffective strategy for social transformation. The more time people spend trying to change individual minds, the less time they have to engage in effective political action that leads to social transformations that eventually lead to changes in popular opinion. So it's a strategic concern: let's focus on political strategies that work rather than waste our time trying to change individual attitudes.
Miles