Regarding the bolded part in green....
Tell that one to a former female friend of my husband.
This article describes her perfectly.
Yet when my husband told her that he was going to propose marriage to me, she went to a male friend of his and told him that she wanted to date my husband. The male friend told her that this was not possible, but she just kept on repeating herself.
Plus there was the time that she invited my husband *who was my boyfriend at the time* to have dinner with her and her parents at her place. That one made me wonder if she thought he was her boyfriend. This was before he proposed to me.
That is an issue regarding a third person who, clearly, has an inability to grasp common social cues. Or has some mental defect that makes her not care. This seems to be the exception, not the rule. So you can't really base the majority around one person that does not represent the general consensus. Nor could you expect an article to make that clear to someone like her.
The topic here, seems much broader, unless your underlying intention was to bring this particular issue up that you faced. If that were the case you should have stated it more plainly. If it's not the case then within the norms my point is valid. A case of confusion between two close people about when things change.
Obviously this other woman had more going on, mentally, as no matter what happened she didn't 'get it'. So with an individual like her, this article doesn't really apply, because there is a deeper, more serious issue that overrides it.
And from what i read of the article it seems to be more geared at figuring out at what point two people go from friends to dating, which is not affected by a 3rd party. That is a decision the two people make together. The suggestion being that the two involved not knowing when that line is crossed, for some odd reason. So i spelled it out quite clearly.