Hitler played very wisely when it came to convincing the people to support him, and the main role in that was that he new perfectly well how to exploit the treaties that were damaging to Germany and build up strong nationalist feeling among the Germans.
Hitler often referred to the sanctions that the treaties had on the German economy, and that the other countries deliberately want to keep them poor and weak. He also used the fact that there were territories where there was dominant Germanic population, but they were under the control of other nations. The treaties also included limitations in the military development and size of the Germans, and Hitler used this to convince the people that that was done in order for the country to not be able to defend itself and to be easily controlled and threatened by the others.