Goebbels was cynic who did not believe in Nazism, but espoused the creed. Goebbels played a tremendous role in popularizing the Nazi ideas, before the Nazis came to power by playing he masses, ridiculing and attacking the opponents. He was a fantastic demagogue telling the masses what they wanted to hear, hammering his own ideas into their hearts and heads. Slogans are like strong drinks to people. The crowd doesn't react like men but like women, who rely on their feelings, rather on their intelligence, if any.
Propaganda is a great, difficult and noble art, therefore it calls for a genius.
The most successful propagandist in history were Christ, Mohammed and Buddha. After the Nazi gained power in 1933, Goebbels had to curb his is attacks, his former enemies were out of power, and the arrogant Nazi leaders could not be criticized. Goebbels was a nihilist that loved to lash out at the dilettante rulers, and was frustrated by this imposed silence. The Jews were the only target available for his sharp tongue, and Goebbels enjoyed having a convenient target. Goebbels did not believe in all the lies he spread so successfully.