Asteroids the source of Earth's water, NASA suggests

From the UK Register:

NASA scientists have provided tantalising evidence that Earth's oceans may have originated in space, supplied by water-packed asteroids which deposited their loads in terminal collisions with our ancient planet.

However, data captured by the NASA Infrared Telescope Facility in Hawaii confirm the continued presence of surface water ice on 24 Themis, suggesting that as it sublimates into space, it's replenished by a sub-surface reservoir.

Don Yeomans, manager of NASA's Near-Earth Object Program Office, said: "For a long time the thinking was that you couldn't find a cup's worth of water in the entire asteroid belt. Today we know you not only could quench your thirst, but you just might be able to fill up every pool on Earth - and then some."

Wait just a second. Isn't the Earth's surface something like 71 percent water? That's a lot of water to come from asteroids.

I call a big BS on this. For one, if this were true, where are these giant meteor craters that were left when all these water-carrying asteroids hit? You'd think there would be some left, right? After all, water (and rock) is pretty darn heavy. They wouldn't have just pulverized when they hit the ground.

Also, saying that there's enough water on asteroids to fill every pool on Earth is nice, but there's a whole lot more water on Earth than that. And let's say some water was brought by asteroids. Are we to conclude that the rest of the water just grew? We know we can't create water out of nothing (if we could we would have a solution to water pollution and drought and a number of other things).

And then what about places on Earth where water seeps from the ground, like in springs and rivers and such?

There's a whole lot here that doesn't make any sense at all. Sound a lot like some "scientist's" pipe dream to me.