How locally a variable is used should matter for selection of a name, too. I don't find i, j, k, o, p, k, v at all offensive if their scope is just a few lines of code. Usage is often idiomatic (e.g., k, v for iterating a map or i for an integer loop variable) and using a longer name would just make it less idiomatic and less obvious.
I also prefer for-loops that uses "i". It is instantly clear that "i" is the current index used by the loop. Even though it is a single character variable name, it has a specific meaning by convention.
If I see a variable named "people_result_list_index" it actually hurts the readability. I don't know that it actually is local to the for-loop, as it could have been defined anywhere in the code or even passed as an argument to the function. It actually hurts readability and adds complexity.
Using "i", "k", "v" and other single character variables outside for-loops is often not advisable. An exception to this could be "x", "y" and "z" if they refer to positions in 2D / 3D space. Personally I would probably wrap them in a structure, so that you could refer to them as pos.x and pos.y. But I wouldn't hold it against someone if they thought the code was readable without it. It is basically part of the domain knowledge. Other domains may have similar exceptions. The "R" value in terms of growth rate comes to mind.
TLDR; Single character variables can make sense in the right context, when they are used as part of a convention or domain terminology
