Earlier quoted context omitted.
A spike in food prices. We can probably weather it OK in the developed world, but last time something like this happened it helped kick off the Arab Spring. Abrupt, large changes in quality of life tend to spark revolutions. They usually get people killed, and often don't result in a more-liberal government taking power.
It is not a worthy thing to do for the US, people should have to adapt to higher prices as a cost of supporting Ukraine. As for the Arab spring, that never had a chance of working. Not even Turkey can deal with democracy and Islam.
Also these aren't just minor increases, e.g. Allianz estimate a 31% increase in prices in 2021; for people who live hand to mouth in the developing world this is catastrophic.