The mass purges were deliberate, while the famine (polemically called the "Holodomor") was not. The famine was caused by Stalin's disastrous agricultural policy, but it wasn't a deliberate attempt to kill people.
[1] https://en.m.wikipedia.org/wiki/Year_Zero_(political_notion)
The Soviets wanted to increase agricultural yield, but the policies Stalin implemented caused the harvest in 1932 to fall by about 20%. In a country already just barely able to feed itself, that led to famine, not just in Ukraine but across the USSR.