We, as Americans, need to respect our country, in the sense that we, as legal citizens, have pledged ourselves to the U.S., what, may I ask, do we say the pledge of allegiance for? To pledge ourselves to the flag. I, as a seventh grader, say it every morning at school. Why? To give my solemn promise to protect that flag. You say it's just a cloth, I say it's an emblem, an emblem we all see almost every day, we wear it, we pledge to it, it's every where we go. That's all that I will say, if you want to hear more, reply.
A person disturbed about a public issue has rights of protest. As long as his actions are not destructive toward others' lives and/or property his actions should be legal. To legally prosecute a flag-burner is a lose-lose contest. The flag-burner loses freedom and/or money, and society loses a possible benefit it might gain from calmly, studiously, and logically considering the protester's assertion, and society loses the tax money spent in the prosecution.
The above pragmatic argument should suffice, but there is another consideration. For the government to insist that I, a free moral agent, ascribe reverence toward any object, person, or thing violates my freedom of conscience, and that governmental insistence is patently tyrannical.
People get to worked up about flag burning. It is no big deal if someone burns a cloth. The only reason anyone cares is because they get emotional about the United States flag. You have the right to be mad if someone burns a flag. They also have the right to burn it.
Regardless of what it represents, a flag is constructed of cloth like materials and colored with various dyes. To add a constitutional amendment would involve a massively unnecessary cost but that cost would be compounded many times in the enforcement. How would you even define an "American flag"? Could a person leave out one row of stars and get off on a technicality? How about burning a red and white t-shirt with a single star on it? The latter is definitely not an American flag but the media would make darn sure we understand the under-lying representation whether or not the instigator denied or asserted it. We live in a free country and need to allow and accept the consequences of that freedom.