Should Congress illegalize burning the US Flag?

I've always said that it should remain legal.  And I truly don't understand why it would be illegal.  I've argued and written essays in college explaining both sides, but I have never been able to really grasp the opposing reasons.  So if you are FOR illegalizing flag burning, please share why. 

And so I'll explain why I believe it should be legal:

1) The United States represents freedom.  Freedom of speech, religion, life, etc.  Burning a flag is an expression.  It's not done to physically hurt someone.  So wouldn't illegalizing that form of expression be contradictory to the freedoms of the United States... which is what the Flag represents?  It would be beyond ironic to make it illegal to burn something that symbolizes the freedom to express yourself (as well as many other freedoms).

2) In the attempts to illegalize it, they always make an exception for boy scouts or proper disposal of a flag.  Which is to burn it (in case you didn't know) when it becomes too torn or tattered. So... what's the difference in burning a flag for proper disposal or burning a flag to make a statement?  Answer: The difference is what you are thinking.  Your reasoning behind it.  So wouldn't illegalizing it really be prosecuting people, not for actions, but for their thoughts?  Sounds like North Korea to me.

There are other, smaller points that just get picky... but these are the main reasons that I just can't get over.  So I request anyone who disagrees to explain themselves in so I can understand why I could be wrong.  In my experience, most people do disagree.  I just don't know why and they haven't been able to explain themselves adequately.

IMPORTANT NOTE - I am very patriotic.  If I see you burning a flag, there will be consequences because I will be personally offended... I just don't think your being offensive is something the government should make unlawful.