The objective of sanctuaries is to educate, show others that we have much better ways of living with animals. Show that they are not here for us to exploit, they are only here to live and be happy as they wish. We cannot continue depriving them of their freedom, we no longer need to consume them to continue living: we have made great progress in the way we eat and dress, we have no need to exploit anyone, anymore.
Moving or relocating animals from their habitat is challenging. However, for sanctuaries, they offer the same natural habitat. They make them feel comfortable by living in an environment they are familiar with and that is natural to them: wild and free to roam.
All occupants inside these homes are fully protected and monitored. Those that have been abandoned and injured are rehabilitated, fed, and treated.
These animal homes also protect them from humans. Some humans have been reported to mistreat and abandon the animals they have brought into their homes pets, such as dogs and cats. They may be left without food, water, and love. Those with deformities also get a chance to live a normal life.
References: https://julianasanimalsanctuary.org/why-should-you-support-an-animal-sanctuary/s