The American thing of keeping cats indoors all the time and thinking that letting a cat roam freely outdoors like basically everyone else in the world does is tantamount animal abuse. That's strange.
we've adopted cats twice, and both times part of the agreement stipulated we could only keep them indoors and never let them out. I think it depends where you live, a crowded urban environment like ours is not ideal for a cat. they contend that even suburban and rural areas can be an issue, where cats can pick up diseases (since they'll eat any damn thing that's laying around or catchable), and small cats can be prayed upon by dogs, hawks and other large birds.