Not that I disagree with the overall point of your post… it’s worth pointing out that the grounded conductor is not always “neutral”, but who knows that, right 
also, people know the service panel as “main panel” because the main disconnect is labelled “main” (per requirement).
And seeing an open ground on your tester , then reporting no ground.
Re-read the initial post of this thread and tell me again how “everyone knows.”
Not that I disagree with the overall message of your post, but I believe you missed the point of mine.
When an inspector refers to the “main” while talking to a client, the client will likely understand that more so than if referred to as the “service.” We agree there.
However, when the inspector doesn’t understand the difference in service equipment and load-side equipment, they are more likely to deliver inaccurate information - as the OP clearly illustrated.
So the intent of my post… For “learning purposes,” an inspector should refrain from using the term “main,” since there is far too much confusion when you have a service panel, a main panel, a service disconnect, a main disconnect, a sub panel, a sub panel main disconnect, etc.
The “cloudiness” can be cleared when you only have “service equipment” and “other equipment.” Once this concept has been thoroughly grasped, the proper usage of the word “main” will be more accurately conveyed.
I would add that for a 120/240 volt system the white conductor, unless reidentified, is always a neutral so calling it such is just fine. It is also a grounded conductor, since the term neutral is more commonplace I would just call it that.