The writer at ELU is saying basically the same thing as De Wit and Brisard, the authors of the paper cited in your previous question, just using different language.
Note that neither of these is trying to "explain" all progressives—they're trying to account for edge cases. The writer at ELU is specifically concerned with the use of stative verbs in the progressive, De Wit and Brisard are interested in a wider range of cases; but both treatments are concerned with situations in which the progressive construction seems to contrast with the simple construction along some other axis than the ordinary perfective/imperfective contrast. De Wit and Brisard locate this axis on a contrast between "epistemic contingency" and "epistemic necessity", and use a little "possible-worlds" terminology to describe it. I don't see a lot of difference between that and the ELU guy's description:
What the form BE+V-ing really does is to indicate that the action or state refered 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.
The "decisions made" thing is one of a range of possible situations in which the progressive might be called into play:
Now that can translate into many things, such as actions that are underway now (present continuous), decisions that have been taken (but might have not been), things that are unusual, things that will take place because of a present decision, or things that the person speaking judges of negatively (I observe it, and I'm not happy about it)...
What the progressive means in any particular utterance is (pace De Wit and Brisard) a matter of pragmatic inference.