Why did JKR not explore H/Hr as canon?

[pippin_999]

No: HPFGUIDX 168767

Phoenixgod:
> Really, where was the subtle hints that she liked Quiddich and was a
> good rider?  if they were there, why did we need Hermione, the
> exposition Fairy to tell us she stole brooms out of the shed (yeah,
> 'cause that's realistic) to learn how to ride?

> There is not a single indication before book five Ginny is even the
> slightest bit sports inclined. She's horrified by the violence of the
> game at the Quiddich world cup and fell asleep during the group talk
> about the game afterwards.

Pippin:
Horrified? But it's horrified fascination not horrified repulsion. 
She's hanging off her seat to watch, not hiding her eyes. And people
do fall asleep because they're tired, sometimes. You can read it
either way.

But in any case, it's not like Harry fell for Ginny because he
found out she was good at Quidditch. So it's not manipulative
that way. 

It does seem a bit egregious on JKR's part if the only reason
she didn't want to let us to know that Ginny was into Quidditch 
is that it'd make H/G a little  too obvious. Why bother
when plenty of us could see it coming anyway?

But what if it's not about making Ginny obviously attractive? 

Harry is going to need a good reason for trusting her with his 
secrets (if he does), and while we knew that she was stealthy 
and secretive in CoS, we didn't know whether
it was all her or just Riddle's influence. Now we do.

Pippin
who agrees with Phoenixgod about the chest monster,
and figures Jo wrote herself between a rock and a hard
place when she promised her audience things wouldn't
get too gritty and then sent her young man off to war.