Fact? Or another hoax?

Who would make such things up? From the Guardian:

There were two babies who had their throats slit. The seven-year-old girl who was raped and murdered in the Superdome. And the corpses laid out amid the excrement in the convention centre.
In a week filled with dreadful scenes of desperation and anger from New Orleans following Hurricane Katrina some stories stood out.
But as time goes on many remain unsubstantiated and may yet prove to be apocryphal.

It sure was picked up by the media and reported as gospel though.

And while many claim they happened, no witnesses, survivors or survivors' relatives have come forward.
Nor has the source for the story of the murdered babies, or indeed their bodies, been found.

Could this be another cannabalism story? Was there rioting and unchecked violence?

Similarly when the first convoy of national guardsmen went into New Orleans approached the convention centre they were ordered to "lock and load".

But when they arrived they were confronted not by armed mobs but a nurse wearing a T-shirt that read "I love New Orleans".....