“Isn’t that how it’s supposed to be?”
That depends on whether or not you believe in the 14th Amendment’s incorporation of the Bill of Rigths as applying against the States.
If, via the 14th Amendment, the Bill of Rights does apply against the States then the Supremes subverted the 5th Amendment of the Constitution and sanctioned governmental theft of private property.
If the Bill of Rights - 5th Amendment - does not apply against the States then the Supremes reached the correct decision regardless of the correctness of their rationale.
That's one way of looking at it. The other way is to look at Article VI. If state and local laws conflict with the U.S. Constitution, and the laws and treaties made under it, then the U.S. Constitution is supreme. If they do not then the state and local laws should apply. When it comes to eminent domain the wording in the state constitution is identical with the wording in the 5th Amendment. Since the U.S. Constitution does not define what constitutes public use then it should be a question for the state legislature to decide. I may not agree with the Connecticut legislature's definition of public use but I agree with the court that that question is best left to the states and not the federal government.