It wasn't Hilary's message, but all during the Hillary Campaign there was a (hired?) army of shills that pushed that kind of shit pretty aggressively across most social media platforms. It's generally assumed that most of these were paid trolls pushing a message from a media/advertising/marketing company or three, because their talking points tended to be pretty similar over stretches of time. The most memorable example was the sudden flood of commenters, opinion posters, letters in local newspapers and speakers at public events who said Bernie Sanders calling Hilary "unqualified" was "Dangerous and irresponsible" and that his statements could be used by Republicans as ammunition against her and that his failure to realize this showed that he didn't understand how politics worked, or something. It was such a consistent and specific message -- and even the same key phrases over and over again: "That is dangerous and irresponsible!" or "Hilary Clinton is the most qualified candidate in history!" -- that people figured out pretty quick that it was more paid marketing than it was actual supporters.
Those same hired shills were also behind a lot of the "Vote for Hilary or you're sexist!" rhetoric. There was a two-week period where anyone who could clearly articulate the reasons they supported Bernie over Hilary (which, if I think about it, includes basically everyone who DID support Bernie at the time) was told "The mansplainers are out in force today!" (Yes, that exact phrase) followed by the suggestion that they should "Admit it: it's time for a woman president!"
If you could call it "interference," it's the fact that most people tended to associate the marketing campaign with Hilary Clinton's campaign, whether it is fair or not. I think a lot of people assumed that she or her office or Debbie Shultz or someone else close to her was personally directing the Shills and helping to organize their marketing push. It's more likely that some company somewhere was hired by a Super PAC to push pro-Hilary messages and simply didn't do enough of the research to figure out how negatively their campaign was being received by just about everyone who didn't already support her.
I think if Hillary truly didn't want to be seen as the "Vote for me or you are sexist/racist" candidate, she could have taken some steps to downplay it rather than feed into it. She didn't have to use the slogan "I'm with her". It made her sound both self-entitled and pushing her gender, as the emphasis was usually on the last syllable and often followed by the "its about time for a woman president" line by those you speak of. They really should have pushed "She's with you" or something like that.
Anybody remember that one debate where Bernie told Hillary to wait her turn after she interrupted him and we then heard accusations of him being "disrespectful to women" and the Bernie Bro nonsense? And when Madeleine Albright introduced Hillary at a Hillary event saying there is a special place in hell for women who don't support Hillary? Is that now so forgotten?
She also could have pushed for truly progressive policy as Bernie did and could have pushed a message of unison rather than division, as Obama did before her. Remember Obama's "Yes We Can" and "There is no Red America or Blue America. There is no Black America or White America. There is the United States of America"? Hillary instead came across as the status quo "No, We Can't" candidate and we were constantly hearing about the "black vote" and "latino vote" and "women vote" etc as if these groups of people are monoliths. And it certainly didn't help that she was running against Trump with his own pushing of identity politics (creating an other to fear). The identity politics in this election really was stark, and was pushed by both the Republicans and Democrats for different reasons and from different angles.
