Arendt, August., evil

Augustine and Friendship:

I find myself challenged by a claim that I found in Dr. David Grumett's "Arendt, Augustine and Evil" from Heythrop Journal XLI (2000), p. 154–169. His essential argument is that Hannah Arendt got her conception of evil from St. Augustine (on whose idea of love she wrote her doctoral thesis). The part that I find counterintuitive is this part:

The solace of
friends was a source of repair and restoration for Augustine in his early
dissolute life and – this is the key point – a substitute for God. ‘This was
a vast myth and a long lie’ because the flattery of this kind of friendship
is corrupting (C 4.7§13 and 9.8§18).

"C" in this case is the Confession, which is available here.

I'm wondering if this isn't an incorrect reading of Augustine. But rather than say why I think it isn't, I'd rather hear what you think about the proposition: is it correct as a reading of Augustine?

Perhaps more importantly, if it were correct would it be right? Confer Chesterton's Femina Contra Mundus:

The sun was black with judgment, and the moon
Blood: but between
I saw a man stand, saying: 'To me at least
The grass is green.

'There was no star that I forgot to fear
With love and wonder.
The birds have loved me'; but no answer came --
Only the thunder.

Once more the man stood, saying: 'A cottage door,
Wherethrough I gazed
That instant as I turned -- yea, I am vile;
Yet my eyes blazed.

'For I had weighed the mountains in a balance,
And the skies in a scale,
I come to sell the stars -- old lamps for new --
Old stars for sale.'

Then a calm voice fell all the thunder through,
A tone less rough:
'Thou hast begun to love one of my works
Almost enough.'

Here we have a case of lust -- deeply sinful and overwhelming -- that nevertheless begins to be a step in the right direction. I had read Augustine as saying something more like this: that the love of friends is a good thing, but "If souls please you, let them be loved in God; for they also are mutable, but in Him are they firmly established."

What do you think? Is it possible for sin to be a step in the right direction? Is friendship necessarily, then, 'a sin in the right direction'?