What Jane Fonda is doing now, protesting inside the U.S., is dissent. What she did around 40 years ago, sitting on an NVA AAA gun, is treason.
Now, the fact that any number of the hundreds of thousands of men and women who served in Vietnam would pour gasoline on Jane Fonda if she were burning is not a sign of what is wrong, it is a sign of what is right. Even though she was not prosecuted for her acts of treason (reason being she took a popular stance against an unpopular war, and those who should have prosecuted her were guilty of cowardice for not doing it) that does not excuse or absolve her guilt, nor does it mean those she committed the acts against are duty bound to forgive her.
Were she not guilty of treasonous acts years ago, no one would feel so strongly about her getting what she has coming to her. She crossed the line when she POSED WITH THE ENEMY. No one is required to forgive her, and that she is so stupid as to do it again and reopen old wounds only means she didn't learn anything from the first time. It does not mean she gets a free pass under "dissent" this time, because few doubt that she'd go pose with Bin Laden given the chance.