Three thoughts come to mind:

1) As long as Bush leaves office at the end of his term peaceably and lawfully, I don't much care what his grandfather thought, did, stood for. Very few of us could vouch for or condone or defend everything each of our forebears thought, did, stood for.

2) 'Skull and Crossbones' is an old 'institution', one that many Americans joined. Pesumably not ALL of those Americans were traitors.

3) Every country in this world has its skeletons and is facing the same dangers. The USA is not alone, not even close.