Ian Smith was an honorable enough person but only a delusional person would think that a white only government can be maintained in a black majority African country. A delusion apparently shared by yourself.
Smith’s actions radicalized politics in that country and contributed to the rise of Zanu-PF.
I think he was desperate, and white rule was probably not morally justifiable, but you have to understand the climate in which those actions were taken and that in which the war was lost. When the whites tried to fight for it, they were flanked by two Portuguese colonies with which they could coordinate their counterinsurgency (Portugal had a military government at the time, determined to keep Angola and Mozambique), with South Africa as an ally to the south (dealing with their own insurgency). The overthrow of Portugal’s government was the kiss of death, as it put the former allies on the flanks in the hands of governments assisting the blacks in Rhodesia instead, while denying the whites assistance and arms. The white Rhodesians felt betrayed by a home government for which they had fought in 2 world wars; as far as who was right or wrong they can sort that out themselves.
I’m Irish; we had no colonies (being one ourselves), so I have no horse in this race. I do see that the lib lessons of the 1970s and 1980s have borne fruit, as many Americans here seem to have bought into the publicly disseminated nonsense about whites abusing blacks for their entertainment.
Oversimplification.
After UDI politics did indeed become more radicalised, leading to the "bush war", actively encouraged by leftists in the west not to forget the USSR. The elections were like recent EU votes, keep voting until the "correct" result (Mugabe) then go home.
Zanu-PF was created after independence as a settlement to halt the near civil war post-1980 with Mugabe's Zanu (Shona) massacring anyone (Ndebele) supporting Nkomo's Zapu.