No they did not. They made an observation about a related field.

That said, animal abuse is correlated with human abuse

We treat animals worse than humans. Even pet animals are often sent to an overcrowded shelter where animals are killed according to the "first in first dead" principle.

If you want to know what cruelties humans are truly capable off I suggest you look at how we treat animals. As long as we declare a certain subgroup of humans "inhuman" we will treat them the same way.