Please, take a look at this answer from English.SE. I am interested in understanding the precise meaning behind the ninth paragraph:
What the form BE+V-ing really does is to indicate that the action or state referred to by the verb in question is presented by the person speaking as actualized (that's the mental operation marked by the suffix -ing) and that this actualization is intimately linked to the situation under consideration (which is the core value of the verb BE). In other words : the action/state is specifically true in this situation to the (possible) exclusion of other situations.
Can anyone explain in in simpler terms? The wording seems too complex for me to comprehend. I am not interested in hearing why this answerer's view is wrong or right: I am merely interested in knowing what the paragraph means exactly.