The Tin Drum, Gunter Grass

Book One, Chapter 10
Shopwindows

There is a lot going on in this chapter. I need help working it all out. I think the theme of the chapter is:

"In those days you could get the better of people on and in front of a grandstand with a paltry tin drum, and I grant that I developed my stage trick, as I had my long-distance, glass-slaying song, to the point of perfection. I didn't just drum down rallies in brown. Oskar sat under grandstands of Reds and Blacks, of Boy Scouts and the spinach shirts of the PX, of Jehovah's Witnesses and the Kyffhauser Bund, of vegetarians and the Polish Youth Fresh Air Movement, Whatever they had to sing, to blow, to pray, to proclaim: my drum knew better."

Is that just a condemnation of easily misled common people? You can "get the better" of them with a "paltry tin drum", you could fool them with nothing more than noise. And, by extension, if that did not work, you had to do some minor damage (break some glass).

Well, I can add that Hitler and Goebbels would remark to each other how easily the commoners would seem to just believe in whatever they were told.
The other comment is that after a few years, the Brownshirts (or SA), under Ernst Roehm, got to be very professional with their bullying tactics. They would just dominate by their physical presence and discipline any kind of public gathering or debate or political event.
To me, then, this chapter is schizoid Oskar: wishful thinking that he could (or could have) controlled those murderous lunatics, but then acting like them himself through his power and arrogance. And all the time enjoying the excitement of the times, his power and the sheer intensity of the moment.
The last comment is the Nazi use of "The Big Lie". Little lies are easy to question, but a stupendous whopper that is repeated often enough somehow becomes above questioning. "I mean, like, if everyone is saying it, then it must be at least partially true, right?" So is Oskar telling us, somewhere, a big lie? To be specific, is Oskar intentionally lying to us about something so big that we do not have the guts to question it? I said earlier I think he is sincere. But I am not sure of this - at least one of his schizoid selves might be taking us for a ride.