There is a reason why they took pride in what they were doing.
First, look at the SS. The SS was created as a pseudo military organization to compete with the SA, the “brownshirts”, who were mostly political thugs and criminals, whose growing power threatened Hitler.
The SS was designed to have high credibility and discipline. This was done by recruiting educated men, many of whom had advanced college degrees. Once organized, this far more professional organization’s first assignment was to wipe out the leadership of the SA.
They did this with some relish, as they despised the loathsome SA criminal scum. But in turn, they presented an even worse threat, were they to remain in Germany, so they were remade into the Waffen SS, and tasked to fight on the front lines next to, but not as part of the army.
Of all things, the SS was under the Finance Ministry, whose duties also included the concentration camps. And so the SS was subdivided into the Waffen SS and the General SS.
Unlike the Waffen SS, the General SS was populated with the same kind of men who had been in the SA. They were intended from the start to commit heinous crimes.
So, and this is my point, take some street punk, put him into an organization with high credibility, give him a snazzy uniform, as if he was “somebody”, and he will gladly do *anything* you ask him to.
He will “take pride” in doing the most disgusting things.
As a parallel example, the Imperial Japanese Army did much the same thing. They took ordinary men, such as shoe salesmen and innkeepers, put them in uniform as officers, gave them swords and pumped them full of the Samurai honor code known as “Bushido”, and let them know that military aggression would be rewarded.
So they “took pride” in committing war crimes like there was no tomorrow.
You are correct, too, the most likely to carry out such orders were picked. But Germany didn’t have that many “thugs” These folks doing the study fail to point out the consequences of disobeying orders in those days.