The Kulaks (who, yes, were monsters and did engage in sabotage in the past) didn't actually have much to do with the famine in the 30s, as they had already been pretty much completely eliminated by that point. Conquest is citing the official statements of the USSR, who blamed the agricultural shortfall on the Kulaks, but the Soviet archives show that the cause was much more complex than that.

Davies and Wheatcroft, in The Years of Hunger: Soviet Agriculture, 1931-1933, explain them. It's hard for me to summarize all of it and the relevant section is only like twenty pages, so please read "(E) CAUSES OF THE FAMINE".

The gist is that planning had overestimated grain yields based on overly optimistic predictions of improvements on previous years' yields. Grain was exported under the assumption that the leftover surplus would be sufficient, but it wasn't. Drought during the growing season and heavy rainfall during the harvesting seasons resulted in low output and high spoilage, meaning much less grain was produced than expected.

The reduction in livestock from 1928 was a product of diverting grain from feed in the countryside to urban population centers. In order to survive capitalist onslaught and develop out of Medieval poverty, the USSR needed to industrialize rapidly, which meant more food for the industrial workers. However, they took too much grain from the countryside to maintain their draught animals, which, coupled with the bad weather, resulted in much lower yields than planned.

When it became clear that a famine was occurring, the USSR did everything in its power to minimize starvation, and Stalin personally pressed for more grain to be reallocated to the countryside. However, the rapidly industrializing urban centers were prioritized, for good reason.

The people who starved were the farmers, mostly in Ukraine, but this wasn't an attempt at ethnic cleansing. Meanwhile, the party used the Kulaks as a scapegoat, even though they didn't really exist at that point. And, honestly, I think that was the right call; they couldn't have just said, "hey, the weather was bad and also we kind of fucked up and that's why you're starving to death", and expected to still have the support of the people. The authors describe this overall response as "ruthless and brutal", an example of a "genuflection to orthodoxy" as Parenti puts it; even though they're in the process of dismantling the narrative of Stalin being a brutal, malicious dictator, they still aren't willing to fully break from it.