There's no right way to do it.
     What's hard is understanding which question you want to 
     ask in any given situation.

I don't see the issue. You admit that answering all of these questions is easy. The hard part is lawyering which question to ask.

This is not a data reporting problem.

This is a data interpretation problem.

A good reporting tool should not be interpreting (or forcing an opinion) on the end user.

You believe this problem is hard because you are forcing an interpretation to exist before you take a measurement. When you should not be interpreting until after measurement. Injecting an interpretation into a measurement process fundamentally changes that measurement.

Measurements inform your interpretation. Not the opposite.

TL;DR You put the cart in front of the horse.

"This is a data interpretation problem."

That's what I said. "Defining it is what's hard."

You seem to understand what I'm saying, and agree with me, but insist on arguing for some reason I cannot comprehend.

     You seem to understand what I'm saying
     and agree with me

Literally the opposite. Your initial statement was

      Measuring memory usage is hard on a modern OS.

Which you've agreed was false as /proc/$PID/maps is easy to read. Then said:

      Defining it is what's hard

But these statements are not mutually inclusive nor does the later imply the former.

I stated measuring is literally the simplest thing. You said ah but what you measuring. That isn't dependent on the tools, or OS. So why did you state it was?

Nooooo... somebody else made that initial statement. My initial statement was "Measuring it is easy. Defining it is what's hard."

Are you just arguing with me because you didn't realize I was somebody else?