While I have to say the truth about Lincoln isn't really shocking—it really didn't matter what he believed about black people being fully equal to whites as long as he was willing to give them the same opportunities—and I'm not certain I agree about Lennon being addicted to violence against women (& some men, notably Stuart Sutcliffe), though I know he did offer it at times ... these are just nitpicks.
Your basic point is well made. Looking closely enough, there are no s/heroes. Even when a historical figure is rehabilitated in area—e.g. US Grant wasn't a talentless butcher, or an incompetent president, but his policies vis a viz Native Americans bear strong criticism, as did Lincoln's—he or she can be savaged in another.