How is it "breaking racial barriers" if you purposely exclude white actors? It seems to me it's more about reinforcing those barriers, not breaking them.
It takes place in a fictive world where everyone is black. There are many fictive worlds where everyone appears to be white (the original Wizard of Oz, for example) and even blaxploitation films have white characters so it's certainly rare. The 'racial barrier' might not mean 'the barrier that separates blacks and others' but a barrier that prevents blacks from creating fictive worlds where they are the 'default' people. (In the Diana Ross film, race is not mentioned).
If someone created an all-female version of 'Lawrence of Arabia', I'd say that would be 'breaking gender barriers', since the original film had no speaking roles for a female character.
(Aside: The Diana Ross-Michael Jackson film version of The Wiz, box office bomb that it was, was nevertheless a childhood favourite of mine and I've seen it a dozen times or more.)
Ease on down the road!


