As a matter of fact, it was said to be less than 10%.
But you 're right insofar as that a crowd can be very dangerous. Deep down, we still want to go with the herd, act with it. Even if you, personally, wouldn't have wanted to perform the nazi greeting, if everybody around you did - would you be able to resist? Besides, this greeting was pretty much forced on people. Those who wouldn't perform it would be looked at sideways, and they had to fear to be investigated. Which could turn out lethal.
Especially the young generation was very much pro Hitler, though. Which is not too surprising as children had been indoctrinated with nazi propaganda from their earliest childhood. There were antisemitic texts and pictures in reading books for first graders (and older pupils, too), and even antisemitic fairy tales! Also, many young people were organized in the Hitler Jugend and its subdivisions. (Officially, every child of 6 years or older had to be a member, although (mainly) in the countryside, this rule couldn't always be enforced.) There, they were indoctrinated even worse, and, with "appropriate" games, the boys were prepared to become soldiers. The girls, though, were prepared to be mothers. (After all, the next generation of soldiers would have to come from somewhere, right?) And all in the name of the Füherer.
