The text in the article certainly expresses they felt Twitter took a long time.

So the headline definitely accurately represents the text... that's better than most headlines these days!

That's subjective.

Isn't the "happy ending" part subjective too?

"Happy ending" at least is editorializing by the article's author instead of by whoever posted the link.

Yes, but it's part of the original title (and a POV of the article itself), not a subjective addition on the part of link submitter.

I think it was objectively a long time to make the transfer. I would argue that 'finally' implies the slowness, not whether it's negative or positive. So the edit is not a problem.