I find this type of thing extraordinarily and deeply disturbing. I was never a fan of most of McCain's policies and I always thought that he was a complex and internally highly conflicted person. He also tended to speak boldly but vote meekly. However I do believe that he did had his own fundamental sense of honor and an image of service to his country that he deeply believed in and which overlapped at least some of my own views. These features, however imperfect, increasingly contrasted with the disgusting abandonment of morality, honesty, moral values, and patriotism by the remainder of the Republican party. And I will respect him for his vote on Obamacare not matter what else he has done.
So to have him defamed not only by the totally immoral Trump, but more generally by the invention of outrageous falsehoods that, in our era of social media, are taken up and spread by raving idiots makes me deeply despair. Yet that is obviously the wave of the future: someone invents facts to advance their own political or social agenda and the true believers take up these "facts" without question (because these "facts" feed into memes that they already believe) and spread them with geometric amplification throughout the internet.
The smearing of McCain (which appears to have been successful based on favorability polls of Republicans) just proves that no one is exempt, even long time committed conservatives. Except Trump, whose favorability somehow is unaffected even by facts easily proven true (often simply by his own words). Perhaps only
completely made up facts about Trump might impact his followers, although I am at a loss how to make up stories more outrageous and disgusting than the real ones

. Sadly however probably a substantial percent of our population will accept as true only what they wish to believe and nothing else.