Earlier quoted context omitted.
Where do people live where going outside for a walk for an hour is that dangerous? I'm pretty sure even if you lived in a super high crime rate area you could still find times to go outside for a walk during the day. Unless we're talking about extreme scenarios like living in an active war-zone.
I'm pretty sure the comment is about cities not built for pedestrians, commonly found in the US.
All the terrible unwalkable cities in the US are called that because you can’t actually walk to anything useful. In other words, those cities that require a car to do errands, go shopping, get to work, go to school, etc.
But for exercise—walking for walking’s sake—it’s usually doable. It is nice if you can get the walking “for free” by combining it with ordinary life, though