They were nuked because people were being offensive and insulting. Simple as that. If it was up to me, or anyone who has ever successfully moderated any sufficiently large forum, they would have simply banned people being insulting to the development team or other SE staff. Saves them a lot of trouble and weeds out the part of the playerbase that shouldn't get a vote anyway.

The thread itself was just collateral damage in the measures taken to get rid of said offensive posts. It's true there was some actual discussion going on, but not much. It's easier to nuke a thread than to delete 80% of the posts and leave an incoherent mess.