AFAIU, there were 2 farmer classes in USSR at the time. Collectives getting fixed price for their crops, and Kulak private farmers getting market prices. Famine makes those prices extortionist, and USSR chose to fight extortion.

USSR leadership absolutely used forced requisition

True

as a tool of power and control and to punish the farmers

Bullshit.

The rapid collectivization of 1929-1934 was a very difficult endeavour, and is the FIRST IN HISTORY successful collectivization of agriculture. There have been many attempts since before the Roman Empire, but never had it been carried our successfully before. Grain requisitions were carried out because the effort of rapid collectivization was kickstarted in order to rapidly industrialize the nation. By introducing tractors into farms and collectivizing them in larger plots, fewer peasants were needed, and people could move to cities to build up an industrial sector. Moving people to cities meant feeding people in cities, and grain requisitions were carried out initially in order to force wealthy exploiter peasants (kulaks) to sell their grain at state mandated prices. Had it not been for the rapid collectivization and industrialization of the 1930s, the Soviets would have been crushed by Nazism, and tens of millions of people more would have been exterminated as it happened in Poland, Belarus or Ukraine. Rapid collectivization wasn't an ideological decision, it was a pragmatic decision that averted the extermination of Eastern Europe at the hands of Nazism.

agrarian population and treated them like shit at least until later in the Union's life

This is again bullshit. The region has never before or after seen the level of expenditure in infrastructure, education or healthcare that took place in rural USSR. Since the disappearing of the USSR, many massive rural exodus have taken place all over the eastern block.

Also Stalin's promotion of Trofim Lysenko and his crackpot ideas on agriculture that mirrored the crackpot ideas of Leninism. Exacerbating famines and helping to kill millions.

The wikipedia article (holomodor), unless it's been nazi washed recently, has/had all the points I made even if it's balanced to "always hate Stalin". I don't know what caused Stalin to not repay US debt (explains food exports), but that too would have led to complaints about his handling of famine. Holomodor is a Ukrainian word, and its enthusiastic eastern cooperation with nazi Germany, including administrating extermination camps, colours its history/politics to this day. Still, they had fewer famine deaths than other parts of the USSR.

Recently, famine/drought in Syria was a great opportunity for the empire and its Al Quaeda and ISIS proxies to rise up and eventually overthrow the long time leader. It is not in demonic evil scum's nature to assist people's survival through cooperation with their government, if a narrative gives them more control over the world.

The USSR in the early years had targeted food shortages in Ukraine and the Caucuses to starve the population into submission

This is a false anticommunist narrative created by western imperialists to boost anticommunism and Russophobia. Plenty of people in Southern Russia died during the 1930s famine, and there is no document proving anything remotely close to your claim of "starving people into submission".

There was later a union wide food shortage because Stalin increased the export of wheat without adequately increasing production

Production was attempted to increase, and achieved subsequently, it simply lagged behind for a few years because, you know, it was the first ever successful experiment of land collectivization in human history, and there were unexpected difficulties that weren't properly addressed with policy at the time. It's easy to judge in hindsight, but the authorities really did everything they could to minimize the famine.

As for grain exports, these weren't a capricious ideological decision, they were forced by the threat of external invasion. The USSR in 1929 was a preindustrial feudal shithole, conditions inherited from the Tsarist Empire. 80% of people were peasants, and life expectancy was of 28 years of age. The collectivization was carried out in a very rapid fashion in order to pursue rapid industrialization, again not out of ideological reasons. There was big debate in the CPSU against rapid collectivization, but the threat of external invasion (evidenced by the invasion by USA, Britain, France and many more countries during the Russian Civil War for the unforgivable sin of being communists) eventually triumphed and rapid industrialization was pursued.

Rapid industrialization, which necessitated rapid collectivization in order to relieve labour from the fields and move it to industry, was the key measure that allowed for the defense of the USSR 10 years later against Nazism. After yearly growths of 15% in GDP, the USSR industrialized just enough to defeat Nazism, at the horrendous cost of 25 million Soviet lives at fascist hands. Had the USSR not pursued rapid industrialization (only enabled by export of grains, the only product the USSR could offer at the time to international markets given its low level of development), Eastern Europe would have been genocided on an unimaginable scale, and Nazism wouldn't have been defeated in Europe. Tens of millions of lives would have been lost to Nazi extermination.

Furthermore, the rapid industrialization boosted the economic capabilities of the country massively, allowing for universal healthcare, the elimination of hunger forever in the region, and therefore the more than doubling of life expectancy between 1929, when industrialization was kickstarted, to 1955 when Stalin died. People went from having a life expectancy of 28 years to above 60 in this timeframe. This, again, saved tens of millions of lives by any demographic measure you use. For comparison, Brazil went from 40 years of life expectancy to slightly above 50 in that timeframe.