It doesn’t appear that these people know much about cats:
There have been only two other documented instances of interspecies adoption—and never between animals that strongly compete for resources in the wild n December 2018, researchers at the Gir National Park in India stumbled upon a lioness who appeared to have adopted a baby leopard as one of her own. The little male cub, who was around two months old, was seen nursing from the lioness, feeding from her kills and playing with her two biological cubs, who were around the same age as the leopard. This rare case of interspecies foster care left the researchers entirely befuddled; pulished in the journal Ecosphere, they describe the lioness’ behavior as plainly “bizarre.”
From an evolutionary perspective, caring for the offspring of another animal doesn’t make much sense.
Brigit Katz, “In a ‘Bizarre’ Biological Twist, a Mother Lion Adopted a Leopard Cub in India” at Smithsonian Magazine
These people read too much Darwin and his followers. The lioness has not read any of those sources, as it happens.
It is common for felines to adopt other animals’ offspring, including some odd choices. The well-fed feline has milk and needs offspring to take it off. So if she isn’t already overburdened and desperate, adoption is an obvious choice for her.
The main problem comes later. A cat can feed puppies, for example, but cannot provide education for them:
One problem, we are told in the video just above, is that puppies are competitive whereas kittens are territorial. There is a difference between the two temperaments. The puppy grows up to jostle for a place in a pack but the kitten grows up to seek out and defend a territory of its own.
Thus the two, from early on, don’t understand each other. The cat does not understand the importance the dog attaches to hierarchy and the dog does not understand the importance the cat attaches to territory. That—as opposed to some purely human concept of Darwinian competition or “eternal enmity”—is the real basis of dogs and cats having difficulty, at first, accepting each other.
Note: For probably unrelated reasons, as you can read about at the Smithsonian Magazine, the leopard cub died young.
Also, from News: People who teach dogs to chase cats for fun are just bad neighbours and bad citizens. Maybe they are bad human beings too but it is best to obey religious injunctions not to judge others.