It was seen by many normal Germans as essential in ridding the country of those they saw as trying to destroy it.
To begin with, guards were murderously undisciplined - Theodor Eicke was charged with developing systems of *sustainable* cruelty, years before the pogrom of 1938.
It was only as the regime tightened it's grip that the saying emerged,
"Lieber Gott, mach mich dumm, damit ich nicht nach Dachau kumm"
(God, make me dumb, so I don't go to Dachau.)
Dachau didn't appear like our notion of Dachau to begin with.
The concentration camps of the Nazis, in the beginning, looked significantly different to what they became.
Don't be afraid to draw comparisons. In fact, it's vital that we do.