You're gonna be bothered by how cool I am.

Very well put. You honestly have to WANT to be misled in order to interpret "we now know" that it's Ron and Hermione as, "We know that RIGHT THIS MOMENT, THIS MILLISECOND IN TIME that it is Ron and Hermione (but the rest of time can't be spoken for)." That's just completely illogical. Talk about reaching! It clearly meant, "Now we know," just like when Hagrid told Harry that he was a wizard. You could also say about that, "Now Harry knows" why he did what he did when he was a little kid. The "now" didn't modify Harry being a wizard (he wasn't a wizard for a split second and then return to being a Squib) and the "now" in her interview statement didn't refer to the duration of Ron and Hermione. In both case the "now" refers to "know".

Now we know it's Ron and Hermione.

Now Harry knows he's a wizard.

In fact, that very construction of "it's Ron and Hermione" implies that she feels this to be a truism that transcends time; it simply IS, just like her statement about Harry and Hermione being very platonic friends. They ARE platonic. A truism, a way of describing their friendship forevermore. It doesn't refer to their friendship in a single moment in time and cease to describe it at some point when they cease to be platonic. I doubt that she ever thought she was being confusing about that. The platonic statement, like the "now we know it's Ron and Hermione" statment, needs to be misunderstood ON PURPOSE. Absolute bloody-mindedness is required in order to NOT get it.

That's not something she intended, clearly. She no doubt felt that "platonic" was as clear as she could get. She probably thought she was being pretty clear about Ron and Hermione last summer as well. There's nothing wrong with these statements and there is no reason to require her to clarify; she has done so, repeatedly and with no meanness of spirit or attempt at obfuscation. Anyone saying otherwise is just kidding themselves.