Wow, a lot of replies in this thread are offputting and full of myopias. There are definitely programs that emphasize diversity more than others and those who think that we're beyond issues around diversity are those who don't emphasize it. I've gotten interview confirmation emails from certain residency programs with contact information for leadership in diversity and faculty who are considered minorities, so some programs definitely emphasize this more than others. I think that both the overall academic institution and the residency program it's under can prioritize diversity in many ways, which are readily apparent. Many times you have to see what programs are NOT saying rather than what they are.
One of the biggest commitments to diversity is looking at the leadership structure: Is there a Director or Vice Chair of Diversity? What are the hiring practices for staff/faculty? What are the funding streams to help faculty/staff who are minorities?
Another clue is to look at the curriculum itself: Does the program have a curriculum for teaching issues surrounding diversity, such as privilege, oppression, cultural/ethnic identity, and bias. Places like OHSU and Baylor does this well even when they have a smaller proportion of marginalized populations.
Bigger urban areas definitely have more of this (regardless of being IMG heavy or not) since they come into contact much more often with issues surrounding diversity within their patient and staff population. Places where the privileged class are predominant usually, but not always, don't feel like they need to talk about it because they don't see it as relevant to their personal priorities (which further oppresses minorities). Places like Boston, Chicago, New York, San Francisco, Los Angeles, and Philadelphia come to mind, but not as an exhaustive list.