Is Rowling speaking to us through Arthur Weasley?

I'm not sure what to make of the following passage from The Goblet of Fire:

At this, the Veela lost control. They launched themselves across the pitch, and began throwing what seemed to be handfuls of fire at the leprechauns. Watching through his Omnioculars, Harry saw that they didn't look remotely beautiful now. On the contrary, their faces were elongating into sharp, cruel-beaked bird heads, and long, scaly wings were bursting from their shoulders -- 

'And that, boys,' yelled Mr. Weasley over the tumult of the crowd below, 'is why you should never go for looks alone!'

I have to admit, I don't like the implication that could be drawn from what Mr. Weasley is saying -- physically attractive people are often evil monsters underneath -- and I particularly don't like the fact that he aims this advice at the boys in the group, leaving out the two girls, Hermione and Ginny.

Before I go into that, however, I will state that my even bigger concern is what this could say about the author, J.K. Rowling herself.

Now, I'm the last person in the world to read a novel and immediately attribute anything and everything that is said in the book (either by individual characters or even the narrator) to the author, but we have already seen that Rowling often puts her philosophy, her thoughts and ideas and opinions, into the mouths of certain of her adult characters.

Certainly, Albus Dumbledore is one such character. I think we can safely argue that Rowling uses Dumbledore to voice her perspective quite often throughout the novels. I would argue that J.K., to a lesser or greater extent, often uses other adult characters who take on parental roles in Harry's life (such as Arthur Weasley, Molly Weasley, Sirius Black and Remus Lupin) to fulfil a similar function: to inject into the narrative the author's perspective and philosophy.

So is Arthur Weasley the voice of the author in this scene? Is he speaking a life-lesson not just to the boys in his family but also to all boys reading the novel?

I hope to goodness that is not Rowling's intention since I find the sentiments expressed (that beauty often hides evil, that feminine beauty, in fact, often hides evil while masculine beauty does not, etc.) highly offensive.

But, if the intention here is not to express the author's philosophy, why is Mr. Weasley's comment included at all? It's not funny. It doesn't tell us anything about the Veela or the situation that is evolving at that moment.

The only thing the comment does is make us think a little less of Arthur Weasley. I've written on other occasions how I often feel Mr. Weasley is not portrayed as a particularly admirable character in these books but this is a low point even for him.

The passage also raises another, less serious question: if pure-bred Veela turn into nasty bird-creatures when angered, what happens to part-Veelas like Fleur Delacour when she gets mad?