[desc]

The 'someone' in question probably wasn't the engineer.

I'd bet the engineer was listening to the 'someone' saying things like 'why don't you just' or 'it just needs to do this', or other things including the word 'just'.

I'd bet the engineer tried to explain the realities of how this stuff works, to 'someone' who's job didn't involve understanding what they were asking for, and reacted by demanding with the word 'just' instead of pretending to ask.