I have a about a decade of experience working professionally as well as a volunteer with wild, domestic, and feral animals, as well as working as an interpretive naturalist in a park along side of park personnel with strong academic credentials. As well as with veterinarians for both wild and domestic animals. I have a stong working background in animal behavior as well as some academic training in psychology.
My opinion is that "owning" animals involves a lot of trade-offs. That is why I don't have any animals now. Many cats who are kept indoors do display some behaviors indicating that they have needs that are not being met. And no matter what the owners do, these behaviors continue to manifest themselves. Sometimes at great cost to the owners. The owners have to determine whether or not they can live with these trade-offs.
Most people don't live in areas where there are species that, should their cat kill them, legal consequences could result.