To answer the second part of the question there were those who challenged the shift in policy.
Chief among these was Ernst Roehm (head of the SA). Roehm was seen as quite left wing and was bitter over the fact that after putting out the 25 Point Plan in the 1920s that the NSDAP had moved away from it (the 25 Point Plan was a list of a number of socialist policies that were then pretty much ignored).
Roehm began ignoring Hitler and openly speaking out against him (there were those who suspected that he was planning a coup...... "funnily" enough Hitler had been ordering Roehm to stop using so much violence). Roehm was one of those arrested and then executed, assassinated, murdered, however you want to put it during the Night of the Long Knives in 1934, which was used by Hitler to not only kill political opponents but to clean the NSDAP of its more left wing members.