I think what we're seeing is the solidification of identity in such strong and unyielding terms that anything that threatens that identity immediately triggers a basic survival instinct. At that point, rational discourse is not possible.
People talked about whether the US should enter World War I for years before the German navy targeted US merchant vessels. After the decision to enter, speaking out against the militarization was grounds for arrest. https://www.smithsonianmag.com/history/fiery-socialist-chall...