maybe you guys should stop your free speech spree rite now because USA has proven that uttering certain things can get you locked up for a long time over and over again!! i do understand the argument but there's no reason to go WE ARE THE FREE SPEAKERS, WE SPEAK OUR MINDS!! etc
and a flag doesnt represent the government but the country so why should critisism of a government come through the form of a national insult 
by burning say an AMERICAN flag you dont say you're against the government but rather against everything the flag represents; every single person and idea in that country. it's respectless and disgusting.
but maybe thats a cultural difference between us, im not conservative in any way and ive taken part in rallies where flags have been burned (mostly israeli and american) and i always thought it was a dumb thing to do because a patriotic israeli or american that does his best to work against the actions that the flag burners despise could/would/might be just as offended as someone spearheading such actions. its a disgusting and generalizing action.
maybe to you the flag represents the government but it sure as hell doesn't to anyone i know
so except for a broken free speech i dont really see the arguments for it sorry for disrailing 
The Freedom of Speech is nothing more but the right to the freedom of expression, the right to speak freely without censorship, seek/receive information/ideas.
However, the Freedom of Expression can be limited on a state by state basis, if they can demonstrate that it is necessary. See: yelling FIRE in a crowded theater, saying you have a bomb in an airport....all those are necessary limitations of an Americans freedom of expression since yelling FIRE in a theater can cause a panic and lead to people getting hurt, and saying a bomb at an airport the same.
That isn't to say that your actual Freedom of Expression is TRULY limited, are you prevented from yelling I HAVE A BOMB at an airport? No. Will you get punished for it? Sure. Is that right? Well, I think even in a perfect world you can never obtain a true state of Freedom of Expression, simply because some things
should have some form of punishment on them, hate speech, anything that can cause a mass panic, perjury, stuff like that...
also flag burning is a form of treason?
I do not think it is treason.
IIRC, flag burning in USA works like this:
-Several places do it ritually (The American legion, Veterans, etc)
-You bury it / burn it otherwise (but you can send it to one of the above places to have them burn it)
It is perfectly legal to burn the USA Flag in America in your own yard, however you probably wouldn't want to do it now (9/11 and all that...people are still way too patriotic over that imo). Our Flag Code is fucked up, we break it all the time anyways. You aren't supposed to wear any part of the flag on a costume, and yet athletes do this ALL THE TIME.
So yeah...