So why all the French hate?

EXPLAIN!!!

Or is it just because the french were such an ass for not going to war with US?

There is no rational reasoning behind it. Hatred of the French by your average American stems from both disgust of intellectualism and liberalism. Americans don't hate the French, they hate smart liberals, they've just chosen the French to embody them. They would use any other no-show in the Coalition of the Willing, but Canada is too close to home and Germany reminds us too much of the fact that they know all about tyrannical governments, false pretenses, and justifying war.