Who gives a crap if they were brave?
They signed a piece of paper. There is nothing brave about that act. The people signing the piece of paper were not the ones fighting in the war and risking their lives. They were not the ones who had to suffer through hell on battlefields and watch their friends die, or their limbs get amputated. The founding fathers might have been hanged if they lost the war, but as aristocrats they still had a good shot of making it our alive.
Furthermore, why are we commending their bravery? You know what takes even more bravery? Picking up an AK-47 and shooting at American soldiers who are invading your country, like Taliban members do every day. But I don’t give a shit that the Taliban are “brave” because the ideology they are fighting for is bronze-age savagery. In the case of the founding fathers, the ideology they were fighting for (or rather, commanding others to fight for) happened to be quite enlightened for the time… which is why we should admire them.
As for our “ancestors being really remarkable people and good stock” ... well, most of them were slave-owners. Thomas Jefferson, who I actually admire a lot otherwise, nevertheless raped one of his slaves. In fact, Great Britain, the evil empire from whom we were rebelling, made slavery illegal half a century before America did. Also, few of the founding fathers thought women should have remotely the same rights as men. Many were bigoted against Catholics and Jews. (And needless to say, @bkcunningham, they are probably not your ancestors.)
The founding fathers were not “the good guys” from a goddamn GI Joe cartoon. They were complicated people who lived in an alien culture, and they likely were just as different from one another in their political and religious beliefs as @bkcunningham and me probably are.