9/11 was more concrete than symbolic, a lot of lives and property were destroyed. Burning the flag is more symbolic than concrete; physically, only some cloth is lost.Quote from Messi007:
You know, for some people in the middle east, the 911 was also a "symbolic statement".
Burning the national flag should be ilegal!. It should be a crime!. There's a lot of different ways to make an statement.
If I have a flag made with 51 stars cleverly arranged such that it appears to be a real American flag to the casual observer, and I burn that, then I've probably "outraged" some of those casual observers, but I have not burned an American flag. This indicates the importance of understanding symbolism.
