It's true that cities generate heat - it happens because the energy people consume in their lves from heating, lighting, air conditioning, travelling and so on, leaks into the surrounding atmosphere. The denser the city, the larger (and more localized) the impact.

What you are repeatedly not getting, or ignoring, is that the heat comes from people. It's concentrated in cities because the people are concentrated. If you spread the people out, you spread the heat leakage out. From the article you cited: "A population density of only 100 persons per sq. km exhibits average warming of about 0.8 deg. C compared to a nearby unpopulated temperature monitoring location." The closer people live together, in apartments, townhomes, and small lots, and the more they use mass transit or have short commutes, the less energy they consume per capita and the less heat goes into their surroundings.

Cities do rely on a large agricultural hinterland to support them. That is how it should be. It all the people in the city spread out across the region, they would build on or pave or otherwise destroy a lot of that farmland. Which do you think is better for preserving farmland from development - building new infill apartments, rowhouse and highrises downtown, or creating a new suburban subdivision of ranch bungalows?

You don't want to live in a city, that's fine. I think you're missing out on a lot, but it's your choice. But you should be thankful so many of us do, because it helps keep you fed too.