“Hey John, draw me up some plans for a bank of 50 furnaces, oh, 6 feet long and 2 feet wide”.

“What the hell for? There’s no practical use for anything like that. This is expensive and there’s a war on”.

“Just do it”.

“Screw you, boss, I’ll take up potato farming.”

But then comes the kicker:

“Do it, or you’re in the Army tomorrow heading for the Russian front. I hope your kids can live on sawdust bread”

I don’t know if that’s how it happened, and I don’t excuse it. Maybe they could have just done a crappy job and gotten demoted, i.e. Oskar Schindler. But most people who weren’t meticulous in their jobs was probably singled out pretty quickly.

In all candor, the engineers probably rationalized it away long before it got to that point. They probably thought “this is just government policy, and what did the Jews ever do for me anyway? How many Jews do I even know? I have my own family to look after”.

Again, not excusing it, just thinking about how it might have happened. No question that antisemitism was the norm at that time.