I wouldn't go so far as to say that we should rejoice to have foreclosures, and that they are a net benefit to society and the economy. Frankly, we would have been better off never having leant large sums to people who couldn't pay it off to begin with. The global economy would be SO much more productive if we hadn't had all the mal-investment in residential dwellings due to the easy credit sloshing about in the last 20 years.
That said, foreclosures are by far the best way to work the excesses out of the system, and get us back to a rational economy. We certainly don't have to view foreclosures like the plague.