If the situation were reversed, these kinds of defenses would not convince the people making them that rural dwellers ought to subsidize urban living.
Education, healthcare, transportation, retirement -- these are all things where we could say "People can just pay for these things if they value them", but instead we determined that some subsidies are good for the country as a whole (we often even want more subsidies for some of these).
Likewise, it's important to have a population that's willing to live and work in rural industries that supply big city centers. Subsidies to provide some of the infrastructure that more dense areas have can help the nation accomplish that needed population mix more easily.
You can shuffle the board around however you want, but the truth is that agriculture (and therefor rural life) is going to be paid for one way or another.
The status quo is that people indirectly pay for food through taxes, higher service cost, and other distortions that have no relation to how much food they consume. They are forced to pay a subsidy whether they like it or not.
Don't forget foreigners: If your country has a subsidized food production system and you're exporting food, then foreigners are benefiting from your subsidies. (This is actually a debate in Canada vs. USA regarding milk.)
"Let them eat cake"