I'm still trying to get my head around this, too. There are a few good posts trying to explain this. Read this one:
http://www.democraticunderground.com/discuss/duboard.php?az=show_topic&forum=104&topic_id=3940035 Here's my stab....
Far right corporatists oppose this ruling because it strengthens the validity of the "takings clause." The Constitution has always allowed government to take private property for the common good as long as owners are compensated fairly. The ruling solidifies this notion and it strengthens government's ability to exercise the public good over private interest.
Unfortunately, in this instance the "private interest" is the little guy, not big corporations. But the ruling will also apply to the big corporations-- ramifications of which are much larger.
Far right judicial groups have been trying for many years to reinterpret the takings clause to apply it to all govt regulation of corporations. For example, passing environment regulation that would lower corporate profits = "taking." They think govt should compensate corporations for the loss of their "property" (profits) resulting from regulation. This would effectively halt government regulation of business because it would cost us too much money.
According to this analysis, this SC case is a perfect red herring. People get outraged over govt kicking homeowners out their homes. The people then support actions to curb govt's ability to overrule private interest for the common good. Corporatists pounce on this to look like they are on the side of the people. Scalia, Thomas, et al. then use this opportunity to twist it so corporations get all the benefits and people get screwed. It has happened many times before.
We're outraged right now because its the little guy who's getting screwed. We have to pay attention to the "slippery slope." Had the decision gone the other way, i.e., had Rehnquist, Scalia, and Thomas prevailed, we'd be looking at a precedent that can be used to undermine govt's ability to act in behalf of the public good.
This case stinks because private property owned by regular people was handed over to developers so the city could revitalize an area and augment tax revenues. In a democracy we're supposed to have the power to prevent elected politicians from abusing their right to eminent domain by throwing the bums out of office. What we need is more democracy and better-informed voters. We need better rules for protecting the less-powerful. We need to come out with legislation or a Constitutional amendment that will spell this out and not be able to be twisted to give the powerful even more power.