That's false.

Only the "law is invalid" part carries the force of law. The second part is just obiter dictum.

Look at http://www.bverfg.de/entscheidungen/rs20100302_1bvr025608.ht...

The four bold points after "Urteil" and before "Gründe" are the legal holding. The rest is just explaining the holding.

Not even the "Leitsätze" on top are binding in any way. But with those, at least, you can argue that the court indicated pretty clearly that it considers those sentences important, making speculation about future verdicts at least a little bit fruitful.