

My roof? It’s hard to burn wood when you don’t have a fireplace. In summer of course we do it outside. But with the density of a city center that means that it’s hard to store enough wood/coal to make meaningful impact on the amount of water you need to boil to cook.
In winter it would be simply counter productive to go outside and be cold to boil rice.
It’s simply easier - and safer - to have water for drinking and food for eating.
Population centers have different needs.
I, myself am prepared to do it in winter in an apartment.
My discussion is not on the how, but on how you fail to perceive that not everyone is yourself. Some people are more able, others less, some have a studio apartment, others a farm. Some live paycheck to paycheck others don’t. Some have 6 people in their household others do not :)
One size does not fit all. What is easy for you, might not be for others and vice-versa.