The reason why the NSDAP shut down secret societies is because they were a source of infiltration by the bolshevik/communists trying to overthrow the government. The same reason applies why Jews were not allowed to congregate in bars and theatres, because those became meeting places to plot subversion.

The "Night of the Long Knives" was a point of reckoning for Hitler. It is true that there were ties between the Sturmabteilung and Hitler in the beginning, as the Treaty of Versailles after WWI had limited the official German army to 100,000 troops. The SA was part of Hitler's effort to regain Germany for the German people from the bankers who were intentionally destroying the country from within during the Weimar Republic. These elites were largely Jews, hence, the propaganda claiming how "evil" the SA was. The Jews were heavily targeted.

However, over time, the SA began having visions of their own Germany, under their rule. Hitler's close friend, Ernst Rohm, the leader of the SA, essentially betrayed Hitler and began acting on his own. Hitler realized this, and urged by his other staff, ordered the capture and disbanding of the SA during the "Night of the Long Knives" in 1934.

Propaganda claims that the SA was behind the Kristallnacht, which has since been proven to be not true. Kristallnacht was a Jewish false flag, perpetrated by communist bolsheviks. Also, claims that the SA were relevant in later political/military actions of Hitler are also false, as they were eliminated shortly following Hitler becoming chancellor.