I cannot possibly agree with that assertion. If anything the 1920s were about forging the foundations of intellectualism, anti-patriotic fervour and pacifism.
Anti-patriotic fervour? No. Politically, the first half of the 20th century in Europe, including the 1920s, was all about ultra-nationalistic fervour. That tendency was only reversed by the massive carnage that Europe saw in WWII, which eventually led to relatively peaceful, non aggressive political stances all over Europe.