Usurpation?

One thing I don't understand about the Hobby Lobby case is how Congress can get away with telling the Supreme Court how to interpret the Constitution, as it did in the RFRA law. There's something about that that seems like an usurpation of the Court's judicial review prerogative.

RFRA instructs the court to use the strict scrutiny standard to assess whether a law is Constitutional viz a viz burdening the free exercise of religion.

How is it ok, legally speaking, for Congress to instruct the Court what standard of review to use? Congress can't tell the President what criteria to use when hiring staff.

I know Congress has done similar things regarding civil rights, but I'm still not clear how RFRA doesn't violate The Court's sphere of authority.