On the surface, the war seems to be based on racial differences and apartheid government, but in interviews with White Rhodesians, they seem to think of the conflict as Capitalism versus Communism. Additionally, the large presence of native black troops in the Rhodesian Armed Forces alludes to the idea of an ideological struggle separated from race. Thanks in advance.
u/MisterComrade does a great job deconstructing the mythos of the Bush War here. The motivation behind the UDI was not anti-communist, it was racial. Of course, it's quite silly to think that the UK would hand over power to a Communist dictator willingly. Smith had poll taxes targeted at black people in his elections and the preponderance of the evidence shows that a concern over the loss of white dominance was his main fear.