The cruelty of this is mind boggling. The fact that they kept the animals in small cages for most of their lives, and expected tame behavior, is also shocking to me.
it still going on. Beside all these intelligent pigs and cows, just recently met a dog here in Palo Alto, a Beagle, who was rescued after doing time as a laboratory test subject - her vocal cords were removed so that her bark wouldn't inconvenience the lab employees, her health did took a hit from the lab time and diagnosing her issues and pains with her not being able to voice it makes it much harder. That deep sadness in her eyes...
While it doesn't make easy all that torture and suffering we, humans, imposed upon animals back then the reasons for what happened in the past are kind of understandable in the sense that we just didn't know it better. Today we do know, and thus there is absolutely no excuses, nor for animal testing, nor for pork&beef production (to start with), and the minuscule amount of money being invested in producing artificial meat is just a shame.
Well, when you struggle for survival daily, you have other things on you mind and priority list, I'd imagine.
They didn't expect tame behavior -- the fact that they succeeded (and in just a few decades) was a surprise.