There are lots of snowbirds, but quite a small community of black seniors here. I'm younger, so I'm not sure that I can speak to interactions between the largely white seniors that live here and the few black seniors, but everyone is friendly.
If you are looking for a great place to retire where it is easy to live and the weather is warm, Phoenix is a great place.
But if you're looking to connect with other black seniors, there are probably better choices.