That's arguing for zoos in general. There aren't any zoos with large enough enclosures, only nature reserves. A zoo is putting a large animal in a small enough cage so that the public can wonder passed and look at it, that isn't compatible with a large enough enclosure for the size animal we're discussing.

If you want to go ahead and link me to one of these "ethical zoos" that has a lion enclosure, I'd welcome it.

Here's some info on the conservation efforts they do: http://institute.sandiegozoo.org/species/african-lion

Here's info about where they breed them and care for them:

http://sdzsafaripark.org/wildlife/lion-camp

You can see the small scale here:

https://www.youtube.com/watch?v=Z7jJ6Ag5WlM

https://www.wildanimalsanctuary.org/