Everyone is different, so I say this not to tell you how to feel but just to offer a different perspective:
Walking in urban environments can be its own sort of joy. Cities (well, good ones anyway) are full of life and energy and humanity, have unexpected nooks and crannies, and a rich sense of dynamism and excitement. Even late at night (as long as you're safe), a quiet city can be a source of serenity and melancholic beauty. Writers like Baudelaire and Benjamin described at great lengths the pleasures of flânerie.
Nature is wonderful too, of course! I love a good hike through the forests and mountains...but I also love a good stroll downtown.
No. Urban environments suck to walk around. What you wrote is utter drivel.
If one needs to justify it by quoting authors, that suggests it isn't self evident and they are just trying to justify something that they know isn't good.