I think "dating" has many different meanings and not everyone agrees with them. You seem to use it with the meaning of "are in a romantic relationship". Others use it like "are seeing each other to assess romantic compatibility" while others again use it as "are involved intimately but not or not yet in a committed relationship".

It would be cool if people just said what they meant. But I guess they find some comfort in the ambiguity.

I guess, it depends

Concluded might have been a better term for them to use. It means effectively the same thing but implies the natural expected end rather than potentially some other reason for ending (such as Linus pitching a fit and yanking it early).

It's good to see it's doing well enough to be considered a success despite some of the interpersonal drama around it.

It's actually a mistake done in a hurry, according to a comment by the author of the post below.