I think it depends on the situation and where you live. I grew up on a farm and we always had outside or "barn" cats. After I became an adult and lived in an apartment, I had inside cats. I didn't dare let them outside because I lived right next to the street and I didn't want them to get hit by a car or run away. Neighbors of mine had a small kitten inside and then they put him outside because they said he "meowed" too much. I was so afraid that the kitten would get out in the street, so I gathered him up and took him inside my apartment. I did ask the person that had the kitten if they cared if I took him. They of course didn't care. I still have him and that's been 7 years ago.
I've been back on the farm for a couple years now and all of my cats are country cats. Some of my inside cats had never been outside before and they love to watch and chase the birds, even though they'll never catch one. My cats are outside part of the day and they have their own house that they stay in at night because of the coyotes that lurk nearby. I think being outdoors every day has made my cats healthier because they get more exercise than they did before, plus it's good that they get fresh air and sunshine.
