You are completely entitled to your own opinion, but personally I believe that the 2001 attacks accelerated the divide to the point that it may have made the difference between Trump getting elected or not. Without the Iraq war a whole pile of stuff that laid the ground for Trump would not have happened.

We agree that this was already happening prior to 2001, but I simply doubt it would have resulted in the extreme situation that we have today. Social media, similarly is an accelerator, not a cause.