Because someone benefiting from the food might be anti-choice.
Also, stop exhaling, so that your emitted carbon dioxide won't be used by plants to grow and produce food for people who are anti-choice.
"It just means that women and their allies are drying up the flow of organs to strangers who may be their oppressors."
So, wait a minute, the idea here is that there are currently people who are not getting organs because there aren't as many women dying from complications of pregnancy.
The basis of your idea is that if the number of women dying from complications of pregnancy is increased, then there might be an increase in donated organs.
Therefore, you want to reduce the number of women donating organs.
It should be obvious that, even if your assumptions and logic are correct, then the excess deaths from pregnancy complications that would have otherwise resulted in abortions is still going to result in an increased number of donor organs, unless you get 100% compliance (which is not obtainable).
But I sincerely doubt anyone is going to be saying "Hey, we have to make abortion legal, so that women who don't have abortions will donate their organs!"
Because making abortion legal to women who would have otherwise died in pregnancy and refused to donate their organs, would be a
MORE effective method of reducing the number of donor organs from women who die in pregnancy because they can't get an abortion.