How can the American legal system which is so devoted to protecting individual rights
justify itself morally if it jeopardizes, through its own rules, the right of law abiding citizens to personal peace and security?
It's an interesting claim being made. I think it needs more detail and specific instances where this jeopardizing is happening. I am not trying to speak from a zealot's point of view, but I think that the American legal system has one of the best self- corrective measures to ensure that it does not completely subvert the rights of the individual. For example, the Constitution devotes much from the original 10 amendments to the rights of the accused and to provide a sense of institutional fairness and procedural due process to those accused of a crime. While there is a jury trial system, there are also processes of appeals, judicial oversight, as well as other measures which can be theoretically enacted to ensure that individuals are afforded every possible opportunity to reflect their innocence under the law. In terms of the law abiding citizen, here again, the Constitution speaks quite profoundly in guaranteeing a sphere in which individuals can be afforded a shield from excessive institutional encroachment. The notion implicit in the First Amendment to be given a sphere of "negative liberty," the right to express oneself to be left alone, is something that every citizen possesses as an entitlement to not be harassed or molested from the external body. Without a specific example, I can only point to the American legal system's theoretical notions that seek to protect the rights of all citizens.
The question is an American National Government assignment. I have that one as well. The book we're using is "Government By the People (Brief)" by David R Magleby (Brigham Young University), Paul C. Light (New York University), and Christine L. Nemacheck (The College of William & Mary). Published by Pearson Education, Inc. Reading assignment for this particular work was chapters 11 & 12. I disagree with the assignment as well. That's how I wound up going through all of this to find more information. I think what the question is referring to is the freedom of speech and how some people (Reverend Fred Phelps Sr. and his church) used it to lawfully picket the funerals of soldiers killed in Iraq and Afghanistan. Also, how their picketing funerals of people they did not know harmed the families of those soldiers. The picketers, although legally stating their opinions, violates the rights of those people to mourn their loved ones in a dignified manner in a private ceremony. This is and other abuse of the constitution is what the question is referring to.
ISBN 10: 0-205-93602-4
ISBN 13: 978-0-205-93602-1
There is an assumption in the question which is not correct. The assumption is that individuals have some unlimited and unrestricted rights, and that the American legal system is intended to protect such unlimited and unrestricted rights. Reality is that the American legal system as well as legal systems of all democratic countries are intended to secure and protect only such individual rights that do not interfere with similar rights of other individuals, and that do not create major problems for the smooth functioning of the country or the society.
The justification for all such legal systems is the general good of the entire society that benefits all the individuals who submit themselves to the discipline of legal system of the society.