I could reduce the level of acrimony on this board at least a bit by never writing about the demographics of intelligence and giftedness
This is very true - I feel that that whole train of thought is outside the purpose of this board. Why is it that such a high percentage of the time we talk about politics, it's this particular story?   
but I think these are important topics with big implications for educational policy
 If this is an important topic (and not a great way to get people off track, as 
I suspect) for educational policy then post on a board where people come to discuss educational policy.  I don't set the U.S. agenda for educational policy, and I don't get much say in it.  For now my number one concern is my own child's eduation. Even though I vote in my local elections, it's the whole package, never line-items.
The only time I want to hear about politics here is if someone is running for office, fighting an age discrimination case, visiting their representitives to talk about giftedness, or their child is writing a letter to the editor.  
But what I like is that I've noticed that when you have a 'political' topic to discuss, you start a thread about it, so that folks can choose if they want to be part of it or not.  Bostonian, I notice that you are very careful to only bring up these ideas on threads that are clearly 'big ideas' thread, and I really appreciate that.  Maybe you are creating a model for how to deal with difficult topics?  
Thanks,
Grinity