It will always turn into a flame war because most of these threads are either posted by activists, or they attract activists. Activists are not interested in a 'conversation', they post to win control of the thread by calling in a brigade to out post and down vote the other side.
Anyone can put together a brigade of a few hundred people in a matter of minutes on reddit or irc.
You have two options in this environment. You can have a politically neutral technology focused board and remove the incentive for activists. Or you let them run a muck and turn your board into a signal booster for there activism and destroy the commuinity.