I just found out about this, and was astonished at he irony of the act of releasing these doves which are specially bred in captivity all their lives. Most of these doves die on getting released.
I agree, Doves & Pigeons are social birds and depend on many urban things. Like, they build their nests only on hard surfaces (sheds etc.). On top of that, they usually have more predators in the wild than in urban areas.