Yea, but it is an irony that matters greatly to understanding these men. The scare quotes are not needed, because it was a real moral quandary that Franklin, Jefferson, et al., recognized and spoke openly about in their own time. It was an irony they wrestled with, and one our country still wrestles with to this day. I can understand your point to an extent; there are those who are quick to find reasons to dismiss history rather than engage with it, and try to make history a morality play of good and bad guys.
That being said, no serious scholar or student of history can ignore the question of slavery during the Revolutionary and post-Revolutionary time periods. It simply looms too large. Indeed, that Declaration of Independence you mentioned? In its original draft it acknowledges slavery as an evil institution, and lays the blame on King George for pushing slavery on the colonies. Jefferson was obviously stretching credulity to lay the blame solely on the king for slavery in North America, but he understood it to be evil and wanted it stated as much in what would be the nation's most important founding document. It was later excised in order to not offend the southern colonies. It simply looms too large.