[Mob]

Cultural lens or personal bias, presumably. While some inspirations, homages or crafting techniques can be readily identified as intended, the reader can often draw comparisons that aren't really there based on what they bring to the text themselves, and even make a case for it.

I could probably make a good argument that John Grammaticus in Legion is basically Zakalwe from Iain M Banks' Use of Weapons with the edges filed off, but I don't believe for a second that it is in fact the case. More like similar ground and my own personal bias (I read about Zakalwe first and like the character) makes me draw the connection.

 

[Mob]

In sorry but comparing anything in 40k to America is just plain wrong

Well, there's the odd outlier like Sly Marbo. But I was more going for the idea that everyone has a cultural or personal context that gives them some reason to draw a comparison where fiction is concerned.

 

[Mob]

As a total aside, I learned (thanks to the General Election in the UK) that "theoretical" and "practical" are terms used by statisticians when analysing polling.
So, uh. That's completely irrelevant. But something I noted.

The idea is surely just a 'Ultramarine-y' way of referring to something many militaries do (as well as problem-solvers in other fields).

I'm reminded of a section in a Neal Stephenson novel when a US marine who achieved hero status for defeating a Japanese infantry assault was interviewed about his tactics when presented with such a situation, so others could learn from it.
He answered "You kill the ones with the swords first"
The interviewer asked if this was a strategy based on the theory that the one with the sword was the officer of the unit. They reply was
"No, you ******* it's because they run at you with a ******** sword! You ever had someone running at you with a ******** sword?!"

Theory meets practical.