It was a white supremacist settler state in southeast Africa which was overthrown by a communist revolution*. Its own variation on an apartheid system was marginally less open about its racism than South Africa's, but was crafted to achieve the same result (similar to Jim Crow laws in the US) while trying to avoid the international condemnation that South Africa was receiving by maintaining plausible deniability (obviously the only people taken in were credulous fools and white supremacists who wanted in on the plausible deniability themselves).

It became a symbol for western fascists during its civil war when it heavily recruited european mercenaries and became a rallying point for white supremacist militants, and after its apartheid government was ousted and the revolutionary state took power (and renamed itself Zimbabwe) it became a reactionary symbol in a similar fashion to the lost-cause narrative that sprang up around the Confederacy post-reconstruction and gets used by white supremacists in the same way as Confederate symbolism except with added anti-communist elements and with the same plausible deniability that Rhodesia itself tried to maintain. Because its symbols (which include the camo pattern used by the mercenaries who fought for it in the civil war) are comparatively more obscure than Confederate ones their use tends to pass without notice among liberals.

* There were multiple distinct communist factions in the civil war, primarily the USSR-backed one and the PRC-backed one, and the latter more or less massacred the leaders of the other one and absorbed its rank and file in the middle of the civil war. Their actions after were similarly opportunist, even though they still deserved critical support for overthrowing a brutal apartheid system.