In the context of the times, the late 60s-early 70s were a time of political concession from both the USSR and the US. This was the Detente period of the Cold War, when the two sides were trying to sign nuclear arms treaties to avoid mutual annihilation like they faced during the Cuban missile crisis as well as the expense involved with making tens of thousands of nukes, and the US was trying to pull itself out of Vietnam and needed good relations with the USSR to make sure they wouldn't have to fight a 2nd Vietnam war if the USSR decided to push the spread of global communism. The grain export deal was just one piece in the puzzle.

Each piece should have had its own concession.

That's the kind of inflexible deal-making that makes negotiation impossible in real life. Sometimes I wish time machine simulations were real so we could send people back in the past and let them try their hand at navigating historical global crises. That'll be sure to teach some humility after the umpteenth time the world gets nuked.

The USSR was responsible for spreading death and oppression through out the world. It finally collapsed due to its failed economic system. Subsidies delayed that collapse, delayed the freedom of hundreds of millions and allowing more deaths.

No one was nuking anyone, the Soviet leadership was just trying to maintain their decadent lifestyles at the expense of their peoples.

hindsight is always 20/20.