She has the right to freedom of speech. It is her constitutional right. Accusing Bush of killing her son without an explanation, on the other hand could be a legal matter. Who knows? It isn't really slander, but it is a false accusation. BUT, she does have the right of freedom of speech. Her son died protecting that right.
Yes, some of the replies were rather tasteless. Our fallen Warriors deserve more respect than that. Remember, while we're all at home playing armchair general, these brave Warriors are laying it all on the line. Many are paying th Ultimate Price. More than I can say for many of us here.
Rickamaven has posted some extremely tasteless things in the past (like the 9/11 pic with falling bodies superimposed with G W Bush), but overall, politics removed, is a good guy. He'll never refuse you a request and will always admit when he's wrong (GW Bush excluded).
Let's just agree to disagree.