Is the use of civil disobedience warranted in response to laws that some people feel are unjust?

Yes the philosophy behind the american nation is to stand up for what you think is right even if you stand alone. While I'm not saying to start a riot, if after listening to the other groups argument you cannot conform or find a middle ground a peaceful protest to stand ageist what you view as unjust is always a good thing to do. Even if you find out later that your not in the right you've at least opened peoples minds to a new point of view and your self to a new experience.