I do not know how far this goes into scuba diving, but I recently read an analysis about the participation of people of color in water sports in general.
If you go back a little more than 100 years, the average person in America could not swim, and swimming in general was not a popular activity. Then, about a century ago, this changed rapidly. All across the country, communities built public swimming pools and started providing swimming lessons. This was really one of the first attempts to provide recreational activities for the communities. There were pretty much no public tennis courts, recreation centers, etc. for competition. Those swimming pools became very popular, and suddenly we became a nation of swimmers.
Except for people of color.
For decades, people of color were not allowed in the public pools in most communities. Even in northern communities, public swimming pools were for white people only. In some cases, courts ordered integration, and this took the form of allowing people of color into the pool one day a week, after which the pool would be drained, scrubbed, and refilled for the white customers coming back the next day.
Eventually this went away, but the legacy continued in another form. The white generations who grew up as swimmers passed on that activity to their children and grandchildren. The people of color had no such history to pass on, and their children and grandchildren sought out different activities.