New citizenship rules for Canadians born or adopted abroad are now in effect

If they decided the act needed amending where is the 'insanity' in not appealing and instead moving forward with the amendment?

Because it makes it harder for a future Parliament to change the law since it was resolved by a court decision on a constitutional ground instead of an amendment. Also, it’s not clear the amendment would have passed if it wasn’t necessary to comply with the court decision.