The point is that the factors clearly not specific to Hillary - right-wing smear campaigns against Democrats, exacerbated by bigotry against people who aren't straight white men - are being used as excuses for the factors that are specific to Hillary, namely her unpopularity and subsequent defeat.
If the right-wing smear machine is so invincible, it's hard to explain how or why it proved unable to twice defeat a black man named Hussein, or even to drag his approval ratings down to Dubya territory before he left office. Unless one argues that he just had an easier time of it.
No one is using them as excuses! The only way to read this as "excuses" is if, in your mind, the only acceptable explanation is to blame it 100% on her campaign, which is completely ridiculous given the circumstances and the insanely narrow margin of loss. That is not to say that they're not at fault, but this was a perfect storm of circumstances, of which their bad campaign and mediocre candidate was only part of the problem.
Plenty of Clinton supporters (myself included) have been very critical of the campaign. This whole back and forth we keep seeing is eerily reminiscent of the campaign, where one side would produce a detailed explanation and the other side would yell at us for not giving them the easy, simple explanation (ITS ALL WALL STREETS FAULT!, reinstalling Glass-Steagal fixes everything!) they wanted