Concentrating on the particular aspect of
cruelty, now I'd like to mention other historical and present "culprits": religions (well, at least some of them), superstitions, false social beliefs, ignorance, lies,
lack of education, etc...
Unfortunately, atrocities like the one mentioned in the first post are very old:
Cat-burning - Wikipedia, the free encyclopedia
And then and now, one of the causes is the lack of education and culture. For instance, what about
wolves? Due to all those traditional and stupid beliefs and lies about wolves, many idiots have inflicted a terrible damage on them for centuries, with an unusual sadism. And many other idiots have minimized its importance because they share the same false beliefs. And even now, in the "age of Internet", it is very difficult to eradicate certain absurd myths, in order to spread the truth and knowledge. Let's say this once and for all:
wolves NEVER attack humans. That's a myth. In fact, wild wolves AVOID humans.
They fear us. And in captivity... well... just look at this:
Are they so fierce?