yes, saying the Nazis are responsible for WW2 is a bit like saying that the Americans were responsible for the American Revolution because they started the fighting.
The root causes of WW2 can easily be traced back to the Treaty of Versailles which was imposed by Britain and France on Germany, carving up German territory and imposing punitive reparation payments.
This had the twin effect of weakening the Weimar republic/German democracy from the start since they had agreed to the Treaty and weakening the German economy since vast amounts of wealth had to be transferred from Germany to Britain/France to pay them.
In addition, Germany was obliged to borrow large sums from the U.S. simply to pay the reparation payments to Britain/France. This had the additional effect that when the depression hit and U.S. loans stopped, the German economy collapsed. Germany was the european country hardest hit by the depression with 6 million unemployed.
All these factors allowed the Nazis to take power in Germany which led to WW2.
If the Versailles treaty had been more fair, more along the line of Wilson's 14 points and if the Weimar Republic had been supported, the Nazis do not come to power and WW2 does not happen.
...so yes, Britain and France are responsible for WW2...
p.s. - As I have stated previously, one of the best books to understand WW2 is "The Wages of Destruction" by Tooze. He goes into the pre-war economic forces in much more detail then I ever could. Highly recommended reading.
http://www.amazon.ca/The-Wages-Destr.../dp/0143113208