Your second paragraph gives a single example which is apparently supposed to support that conclusion. That's a definitional example of cherry-picking and hasty generalization.
The projection comes in because it's difficult to see how you would reach those conclusions from the available evidence, unless you're projecting.
And if you want more evidence than that, then I suggest reading about Stanley Milgram’s famous experiments. A little quote:
Moreover, even when the destructive effects of their work become
patently clear, and they are asked to carry out actions
incompatible with fundamental standards of morality, relatively
few people have the resources needed to resist authority.
If you're unaware of all the criticism of Milgram's experiments, then you have some studying to do before we can have a meaningful discussion about this.
While you're catching up on the history of social psychology since 1961, you might want to ask yourself why it is that you're so eager to believe that "ordinary people are mostly evil". Do you have a religious background, perhaps? "Original sin" and all that?
Some of the criticisms are valid, and the results to not reflect well on us as people. The 33% of people who can keep to their stated ethics in the face of authority probably have a really hard time believing that 66% of people cannot. To them it seems easy and obvious that you just don’t violate your ethics. But imagine it this way: for hundreds of thousands of years humans lived in tiny tribes wandering in the wilderness. Failure to heed the orders of the tribe’s leaders would have been a virtual death sentence for most of that time. That environment literally breeds for people who obey even when they think it’s a bad idea. That’s apparently not long enough for the trait to have become universal, thankfully.
I don’t know about the TPSE though. I didn’t cite it either.
There’s a good book called “Ordinary Men: Reserve Police Battalion 101 and the Final Solution in Poland” by Christopher Browning which explores this. The Reserve Police Battalions were created by Germany to police captured territory, but they were seen by ordinary Germans as a way to avoid the war and conscription. The members were not Nazis, and almost to a man they joined because it was an honorable way to avoid participating in the evils happening all around them. They were only trained for ordinary honest police work, but in the end many of them were being used to hunt down and murder Jews. They were sent out into forests to comb them for underground shelters. They rounded up Jews and herded them into mass graves.
Almost none of them complained or tried to avoid participating. No one punished them if they didn’t participate. No one coerced them into participating. A few asked for and received transfers, if I recall correctly. The best that can be said about the rest is that many of them are believed not to have actually fired their weapons. Some of them probably went the whole war without actually killing anyone, technically. They were just assigned the job so they did it.