What you say is true, but not applicable to this situation. It is not judicial activism when an unconstitutional law is shot down. It is judicial activism when a right that is not in the Constitution is created. There is a big difference, and Obama knows that. He, as a student of Alinsky, knows that framing the language is key to the debate. He loves to make words into their opposite.
I question that. The ninth amendment says "The enumeration in the Constitution, of certain rights, shall not be construed to deny or disparage others retained by the people."
The Constitution doesn't specify how those unenumerated rights become recognized, but I don't see that it rules out such by the courts. The legislature doesn't seem to be the correct place because it should be based on a petition from the people who already own these rights.
I've often wondered how the founders envisioned these rights becoming identified and honored.